eml_parser serves as a python module for parsing eml files and returning various information found in the e-mail as well as computed information. Prior to 3.0.2, eml_parser.routing.noparenthesis in eml_parser/routing.py removes parenthesized CFWS comments from Received: headers with a regex-based fix-point loop whose running time is quadratic in the nesting depth. A single Received: header with 5,000 nested parentheses causes approximately 1.3 seconds of CPU saturation per parsed message, and doubling the nesting depth approximately quadruples the running time. An attacker can submit relatively small EML files that consume multiple seconds of processing time, causing worker latency, queue backpressure, and possible service-level outages in synchronous gateways, sandboxes, and real-time triage pipelines. This issue is fixed in version 3.0.2.
Metrics
Affected Vendors & Products
References
History
Wed, 26 Aug 2026 16:30:00 +0000
| Type | Values Removed | Values Added |
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| Metrics |
ssvc
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Tue, 25 Aug 2026 19:45:00 +0000
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| First Time appeared |
Govcert-lu
Govcert-lu eml Parser |
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| Vendors & Products |
Govcert-lu
Govcert-lu eml Parser |
Tue, 25 Aug 2026 18:30:00 +0000
| Type | Values Removed | Values Added |
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| Description | eml_parser serves as a python module for parsing eml files and returning various information found in the e-mail as well as computed information. Prior to 3.0.2, eml_parser.routing.noparenthesis in eml_parser/routing.py removes parenthesized CFWS comments from Received: headers with a regex-based fix-point loop whose running time is quadratic in the nesting depth. A single Received: header with 5,000 nested parentheses causes approximately 1.3 seconds of CPU saturation per parsed message, and doubling the nesting depth approximately quadruples the running time. An attacker can submit relatively small EML files that consume multiple seconds of processing time, causing worker latency, queue backpressure, and possible service-level outages in synchronous gateways, sandboxes, and real-time triage pipelines. This issue is fixed in version 3.0.2. | |
| Title | eml_parser: DoS via deeply nested parens in Received headers | |
| Weaknesses | CWE-1124 CWE-770 |
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| References |
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| Metrics |
cvssV3_1
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Status: PUBLISHED
Assigner: GitHub_M
Published: 2026-08-25T18:26:54.978Z
Updated: 2026-08-26T15:34:18.389Z
Reserved: 2026-06-16T23:31:22.446Z
Link: CVE-2026-55620
Updated: 2026-08-26T15:34:14.913Z
Status : Deferred
Published: 2026-08-25T19:16:50.627
Modified: 2026-09-09T21:07:31.353
Link: CVE-2026-55620
No data.