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.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
|---|---|---|---|---|---|---|---|---|---|
| GOVCERT-LU | eml_parser | affected |
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Project Subscriptions
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Advisories
| Source | ID | Title |
|---|---|---|
 Github GHSA |
GHSA-g7gc-gmgp-wgqg | eml_parser vulnerable to DoS via deeply nested parens in Received headers |
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Tue, 25 Aug 2026 18:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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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Projects
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MITRE
Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-08-25T18:26:54.978Z
Reserved: 2026-06-16T23:31:22.446Z
Link: CVE-2026-55620
Vulnrichment
No data.
NVD
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Redhat
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OpenCVE Enrichment
No data.