A stack-based buffer overflow flaw was found in the X.Org X server and Xwayland. The X server has multiple stack buffers sized XkbMaxShiftLevel * XkbNumKbdGroups but CheckKeyTypes() does not verify or clamp non-canonical key types to XkbMaxShiftLevel. A client can change key types to excessive shift levels and trigger stack overflows. This is caused by an incomplete fix of CVE-2025-26597. This may be used to crash the server, or for privilege escalation if the X server runs as root.
Metrics
Affected Vendors & Products
References
History
Mon, 08 Jun 2026 17:30:00 +0000
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| Metrics |
ssvc
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Mon, 08 Jun 2026 17:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
X.org xwayland
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| CPEs | cpe:2.3:a:x.org:x_server:*:*:*:*:*:*:*:* cpe:2.3:a:x.org:xwayland:*:*:*:*:*:*:*:* cpe:2.3:o:redhat:enterprise_linux:10.0:*:*:*:*:*:*:* cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:* cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:* cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:* |
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| Vendors & Products |
X.org xwayland
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Sun, 07 Jun 2026 11:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
X.org
X.org x Server |
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| Vendors & Products |
X.org
X.org x Server |
Fri, 05 Jun 2026 12:15:00 +0000
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| References |
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| Metrics |
threat_severity
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threat_severity
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Fri, 05 Jun 2026 11:45:00 +0000
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| Description | A stack-based buffer overflow flaw was found in the X.Org X server and Xwayland. The X server has multiple stack buffers sized XkbMaxShiftLevel * XkbNumKbdGroups but CheckKeyTypes() does not verify or clamp non-canonical key types to XkbMaxShiftLevel. A client can change key types to excessive shift levels and trigger stack overflows. This is caused by an incomplete fix of CVE-2025-26597. This may be used to crash the server, or for privilege escalation if the X server runs as root. | |
| Title | Xorg-x11-server: xorg-x11-server-xwayland: xorg-x11-server: stack buffer overflow in xkb key types due to unchecked shift levels | |
| First Time appeared |
Redhat
Redhat enterprise Linux |
|
| Weaknesses | CWE-121 | |
| CPEs | cpe:/o:redhat:enterprise_linux:10 cpe:/o:redhat:enterprise_linux:6 cpe:/o:redhat:enterprise_linux:7 cpe:/o:redhat:enterprise_linux:8 cpe:/o:redhat:enterprise_linux:9 |
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| Vendors & Products |
Redhat
Redhat enterprise Linux |
|
| References |
|
|
| Metrics |
cvssV3_1
|
Status: PUBLISHED
Assigner: redhat
Published: 2026-06-05T10:31:39.316Z
Updated: 2026-06-08T15:55:03.323Z
Reserved: 2026-06-04T14:55:24.011Z
Link: CVE-2026-50258
Updated: 2026-06-08T15:54:57.873Z
Status : Analyzed
Published: 2026-06-05T12:16:39.070
Modified: 2026-06-08T16:46:48.723
Link: CVE-2026-50258