CVE-2026-80808 - Vulnerability Details

Vendors	Products
Linux	Linux Kernel

Link	Providers
https://git.kernel.org/stable/c/119a2f053242ed75bdd2ebc95baf3ae7db6ccacf
https://git.kernel.org/stable/c/4902a5cba21aeaf91e6b29e20e0967a5f6abdcd9
https://git.kernel.org/stable/c/54b6bd40898de7906acb2bccc9a96d1b8e6b4323
https://git.kernel.org/stable/c/55ee6533c1db7f7656fa8dd19637f3f8b8c08dc5
https://git.kernel.org/stable/c/61631352a5b405c89be579de00903b72e6888aa4
https://git.kernel.org/stable/c/8865cd664484517703df5c18a965dc3227572b87
https://git.kernel.org/stable/c/889ec86464d261f026f6c334040cfc6c58c99d58
https://git.kernel.org/stable/c/a40c45268f4358207aa9c53764fed2e05f62986a
https://git.kernel.org/stable/c/dbd4aea175ad3c46436acb251e817b4374628072

Type	Values Removed	Values Added
Weaknesses		CWE-665

Type	Values Removed	Values Added
Description		In the Linux kernel, the following vulnerability has been resolved: ext4: stop retrying saturated xattr cache entries ext4_xattr_block_set() retries when a cache entry selected for reuse has a saturated reference count after taking the buffer lock. The retry returns to the mbcache lookup without making that entry ineligible, so it can select the same unusable entry indefinitely. A task spinning there can hold the parent directory's i_rwsem and leave concurrent rmdir callers blocked. Normally a reusable entry has a reference count below EXT4_XATTR_REFCOUNT_MAX because the count and MBE_REUSABLE_B are updated under the same buffer lock. A corrupted filesystem can violate that invariant. The syzbot reproducer reports allocator and xattr corruption before triggering this retry loop. Check the untrusted on-disk count before incrementing it, avoiding overflow, and clear MBE_REUSABLE_B when it is already saturated. The next lookup then skips the entry that was just proven unusable. This mirrors the normal transition at EXT4_XATTR_REFCOUNT_MAX; the release path marks the entry reusable again on the exact 1024-to-1023 transition. Using the same QEMU harness and guest parameters, current unpatched Linux hung in 6 of 8 420-second trials with the do_rmdir signature; representative NMI backtraces caught the owner spinning in ext4_xattr_block_set(). The patched kernel completed 28 of 28 trials without a hung-task report; the final twelve trials exercised the reviewed overflow-safe form of the change. syzbot's patch testing also completed without reproducing the hang.
Title		ext4: stop retrying saturated xattr cache entries
First Time appeared		Linux Linux linux Kernel
CPEs		cpe:2.3:o:linux:linux_kernel::::::::
Vendors & Products		Linux Linux linux Kernel
References		https://git.kernel.org/stable/c/119a2f053242ed75bdd2ebc95baf3ae7db6ccacf https://git.kernel.org/stable/c/4902a5cba21aeaf91e6b29e20e0967a5f6abdcd9 https://git.kernel.org/stable/c/54b6bd40898de7906acb2bccc9a96d1b8e6b4323 https://git.kernel.org/stable/c/55ee6533c1db7f7656fa8dd19637f3f8b8c08dc5 https://git.kernel.org/stable/c/61631352a5b405c89be579de00903b72e6888aa4 https://git.kernel.org/stable/c/8865cd664484517703df5c18a965dc3227572b87 https://git.kernel.org/stable/c/889ec86464d261f026f6c334040cfc6c58c99d58 https://git.kernel.org/stable/c/a40c45268f4358207aa9c53764fed2e05f62986a https://git.kernel.org/stable/c/dbd4aea175ad3c46436acb251e817b4374628072

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-80808", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-26T14:34:25.794Z", "datePublished": "2026-09-04T15:13:28.562Z", "dateUpdated": "2026-09-04T15:13:28.562Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-09-04T15:13:28.562Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: stop retrying saturated xattr cache entries\n\next4_xattr_block_set() retries when a cache entry selected for reuse\nhas a saturated reference count after taking the buffer lock. The retry\nreturns to the mbcache lookup without making that entry ineligible, so\nit can select the same unusable entry indefinitely. A task spinning\nthere can hold the parent directory's i_rwsem and leave concurrent\nrmdir callers blocked.\n\nNormally a reusable entry has a reference count below\nEXT4_XATTR_REFCOUNT_MAX because the count and MBE_REUSABLE_B are\nupdated under the same buffer lock. A corrupted filesystem can violate\nthat invariant. The syzbot reproducer reports allocator and xattr\ncorruption before triggering this retry loop.\n\nCheck the untrusted on-disk count before incrementing it, avoiding\noverflow, and clear MBE_REUSABLE_B when it is already saturated. The\nnext lookup then skips the entry that was just proven unusable. This\nmirrors the normal transition at EXT4_XATTR_REFCOUNT_MAX; the release\npath marks the entry reusable again on the exact 1024-to-1023\ntransition.\n\nUsing the same QEMU harness and guest parameters, current unpatched\nLinux hung in 6 of 8 420-second trials with the do_rmdir signature;\nrepresentative NMI backtraces caught the owner spinning in\next4_xattr_block_set(). The patched kernel completed 28 of 28 trials\nwithout a hung-task report; the final twelve trials exercised the\nreviewed overflow-safe form of the change. syzbot's patch testing also\ncompleted without reproducing the hang."}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/ext4/xattr.c"], "versions": [{"version": "1a56cd972ce121b6cf2517a47a578782bbd2ec95", "lessThan": "119a2f053242ed75bdd2ebc95baf3ae7db6ccacf", "status": "affected", "versionType": "git"}, {"version": "1be97463696c7291a3e1547614e96432b0bd3add", "lessThan": "61631352a5b405c89be579de00903b72e6888aa4", "status": "affected", "versionType": "git"}, {"version": "65f8b80053a1b2fd602daa6814e62d6fa90e5e9b", "lessThan": "8865cd664484517703df5c18a965dc3227572b87", "status": "affected", "versionType": "git"}, {"version": "65f8b80053a1b2fd602daa6814e62d6fa90e5e9b", "lessThan": "a40c45268f4358207aa9c53764fed2e05f62986a", "status": "affected", "versionType": "git"}, {"version": "65f8b80053a1b2fd602daa6814e62d6fa90e5e9b", "lessThan": "889ec86464d261f026f6c334040cfc6c58c99d58", "status": "affected", "versionType": "git"}, {"version": "65f8b80053a1b2fd602daa6814e62d6fa90e5e9b", "lessThan": "4902a5cba21aeaf91e6b29e20e0967a5f6abdcd9", "status": "affected", "versionType": "git"}, {"version": "65f8b80053a1b2fd602daa6814e62d6fa90e5e9b", "lessThan": "55ee6533c1db7f7656fa8dd19637f3f8b8c08dc5", "status": "affected", "versionType": "git"}, {"version": "65f8b80053a1b2fd602daa6814e62d6fa90e5e9b", "lessThan": "dbd4aea175ad3c46436acb251e817b4374628072", "status": "affected", "versionType": "git"}, {"version": "65f8b80053a1b2fd602daa6814e62d6fa90e5e9b", "lessThan": "54b6bd40898de7906acb2bccc9a96d1b8e6b4323", "status": "affected", "versionType": "git"}, {"version": "98953044b3cdb2cb7d82e7365b659e2ed4f4ca4d", "status": "affected", "versionType": "git"}, {"version": "af8ecc8d20e72130771cc076bce7fcf17ccda6c4", "status": "affected", "versionType": "git"}, {"version": "c6fac5cf5a5098732623bcd00a8a3eb9f5465144", "status": "affected", "versionType": "git"}, {"version": "96fa141fa295ae9428da73c56c9852053b575c04", "status": "affected", "versionType": "git"}, {"version": "5.10.163", "lessThan": "5.10.267", "status": "affected", "versionType": "semver"}, {"version": "5.15.61", "lessThan": "5.15.218", "status": "affected", "versionType": "semver"}, {"version": "4.19.270", "lessThan": "4.20", "status": "affected", "versionType": "semver"}, {"version": "5.4.229", "lessThan": "5.5", "status": "affected", "versionType": "semver"}, {"version": "5.18.18", "lessThan": "5.19", "status": "affected", "versionType": "semver"}, {"version": "5.19.2", "lessThan": "5.20", "status": "affected", "versionType": "semver"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/ext4/xattr.c"], "versions": [{"version": "6.0", "status": "affected"}, {"version": "0", "lessThan": "6.0", "status": "unaffected", "versionType": "semver"}, {"version": "5.10.267", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver"}, {"version": "5.15.218", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.185", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.154", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.106", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.47", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.1.11", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2.1", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.3-rc1", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.10.163", "versionEndExcluding": "5.10.267"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15.61", "versionEndExcluding": "5.15.218"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0", "versionEndExcluding": "6.1.185"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0", "versionEndExcluding": "6.6.154"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0", "versionEndExcluding": "6.12.106"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0", "versionEndExcluding": "6.18.47"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0", "versionEndExcluding": "7.1.11"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0", "versionEndExcluding": "7.2.1"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0", "versionEndExcluding": "7.3-rc1"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.19.270"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.4.229"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.18.18"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.19.2"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/119a2f053242ed75bdd2ebc95baf3ae7db6ccacf"}, {"url": "https://git.kernel.org/stable/c/61631352a5b405c89be579de00903b72e6888aa4"}, {"url": "https://git.kernel.org/stable/c/8865cd664484517703df5c18a965dc3227572b87"}, {"url": "https://git.kernel.org/stable/c/a40c45268f4358207aa9c53764fed2e05f62986a"}, {"url": "https://git.kernel.org/stable/c/889ec86464d261f026f6c334040cfc6c58c99d58"}, {"url": "https://git.kernel.org/stable/c/4902a5cba21aeaf91e6b29e20e0967a5f6abdcd9"}, {"url": "https://git.kernel.org/stable/c/55ee6533c1db7f7656fa8dd19637f3f8b8c08dc5"}, {"url": "https://git.kernel.org/stable/c/dbd4aea175ad3c46436acb251e817b4374628072"}, {"url": "https://git.kernel.org/stable/c/54b6bd40898de7906acb2bccc9a96d1b8e6b4323"}], "title": "ext4: stop retrying saturated xattr cache entries", "x_generator": {"engine": "bippy-1.2.0"}}}}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["fs/ext4/xattr.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "119a2f053242ed75bdd2ebc95baf3ae7db6ccacf", "status": "affected", "version": "1a56cd972ce121b6cf2517a47a578782bbd2ec95", "versionType": "git"}, {"lessThan": "61631352a5b405c89be579de00903b72e6888aa4", "status": "affected", "version": "1be97463696c7291a3e1547614e96432b0bd3add", "versionType": "git"}, {"lessThan": "8865cd664484517703df5c18a965dc3227572b87", "status": "affected", "version": "65f8b80053a1b2fd602daa6814e62d6fa90e5e9b", "versionType": "git"}, {"lessThan": "a40c45268f4358207aa9c53764fed2e05f62986a", "status": "affected", "version": "65f8b80053a1b2fd602daa6814e62d6fa90e5e9b", "versionType": "git"}, {"lessThan": "889ec86464d261f026f6c334040cfc6c58c99d58", "status": "affected", "version": "65f8b80053a1b2fd602daa6814e62d6fa90e5e9b", "versionType": "git"}, {"lessThan": "4902a5cba21aeaf91e6b29e20e0967a5f6abdcd9", "status": "affected", "version": "65f8b80053a1b2fd602daa6814e62d6fa90e5e9b", "versionType": "git"}, {"lessThan": "55ee6533c1db7f7656fa8dd19637f3f8b8c08dc5", "status": "affected", "version": "65f8b80053a1b2fd602daa6814e62d6fa90e5e9b", "versionType": "git"}, {"lessThan": "dbd4aea175ad3c46436acb251e817b4374628072", "status": "affected", "version": "65f8b80053a1b2fd602daa6814e62d6fa90e5e9b", "versionType": "git"}, {"lessThan": "54b6bd40898de7906acb2bccc9a96d1b8e6b4323", "status": "affected", "version": "65f8b80053a1b2fd602daa6814e62d6fa90e5e9b", "versionType": "git"}, {"status": "affected", "version": "98953044b3cdb2cb7d82e7365b659e2ed4f4ca4d", "versionType": "git"}, {"status": "affected", "version": "af8ecc8d20e72130771cc076bce7fcf17ccda6c4", "versionType": "git"}, {"status": "affected", "version": "c6fac5cf5a5098732623bcd00a8a3eb9f5465144", "versionType": "git"}, {"status": "affected", "version": "96fa141fa295ae9428da73c56c9852053b575c04", "versionType": "git"}, {"lessThan": "5.10.267", "status": "affected", "version": "5.10.163", "versionType": "semver"}, {"lessThan": "5.15.218", "status": "affected", "version": "5.15.61", "versionType": "semver"}, {"lessThan": "4.20", "status": "affected", "version": "4.19.270", "versionType": "semver"}, {"lessThan": "5.5", "status": "affected", "version": "5.4.229", "versionType": "semver"}, {"lessThan": "5.19", "status": "affected", "version": "5.18.18", "versionType": "semver"}, {"lessThan": "5.20", "status": "affected", "version": "5.19.2", "versionType": "semver"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["fs/ext4/xattr.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "6.0"}, {"lessThan": "6.0", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "5.10.*", "status": "unaffected", "version": "5.10.267", "versionType": "semver"}, {"lessThanOrEqual": "5.15.*", "status": "unaffected", "version": "5.15.218", "versionType": "semver"}, {"lessThanOrEqual": "6.1.*", "status": "unaffected", "version": "6.1.185", "versionType": "semver"}, {"lessThanOrEqual": "6.6.*", "status": "unaffected", "version": "6.6.154", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.106", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.47", "versionType": "semver"}, {"lessThanOrEqual": "7.1.*", "status": "unaffected", "version": "7.1.11", "versionType": "semver"}, {"lessThanOrEqual": "7.2.*", "status": "unaffected", "version": "7.2.1", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.3-rc1", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: stop retrying saturated xattr cache entries\n\next4_xattr_block_set() retries when a cache entry selected for reuse\nhas a saturated reference count after taking the buffer lock. The retry\nreturns to the mbcache lookup without making that entry ineligible, so\nit can select the same unusable entry indefinitely. A task spinning\nthere can hold the parent directory's i_rwsem and leave concurrent\nrmdir callers blocked.\n\nNormally a reusable entry has a reference count below\nEXT4_XATTR_REFCOUNT_MAX because the count and MBE_REUSABLE_B are\nupdated under the same buffer lock. A corrupted filesystem can violate\nthat invariant. The syzbot reproducer reports allocator and xattr\ncorruption before triggering this retry loop.\n\nCheck the untrusted on-disk count before incrementing it, avoiding\noverflow, and clear MBE_REUSABLE_B when it is already saturated. The\nnext lookup then skips the entry that was just proven unusable. This\nmirrors the normal transition at EXT4_XATTR_REFCOUNT_MAX; the release\npath marks the entry reusable again on the exact 1024-to-1023\ntransition.\n\nUsing the same QEMU harness and guest parameters, current unpatched\nLinux hung in 6 of 8 420-second trials with the do_rmdir signature;\nrepresentative NMI backtraces caught the owner spinning in\next4_xattr_block_set(). The patched kernel completed 28 of 28 trials\nwithout a hung-task report; the final twelve trials exercised the\nreviewed overflow-safe form of the change. syzbot's patch testing also\ncompleted without reproducing the hang."}], "id": "CVE-2026-80808", "lastModified": "2026-09-04T16:18:07.993", "metrics": {}, "published": "2026-09-04T16:18:07.993", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/119a2f053242ed75bdd2ebc95baf3ae7db6ccacf"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/4902a5cba21aeaf91e6b29e20e0967a5f6abdcd9"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/54b6bd40898de7906acb2bccc9a96d1b8e6b4323"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/55ee6533c1db7f7656fa8dd19637f3f8b8c08dc5"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/61631352a5b405c89be579de00903b72e6888aa4"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/8865cd664484517703df5c18a965dc3227572b87"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/889ec86464d261f026f6c334040cfc6c58c99d58"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/a40c45268f4358207aa9c53764fed2e05f62986a"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/dbd4aea175ad3c46436acb251e817b4374628072"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

Metrics

Affected Vendors & Products

Metrics

Affected Vendors & Products

JSON object

JSON object

JSON object

JSON object