Vulnerability 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.
CVSS Score
HIGH
Related Weaknesses (CWE)
References
- https://github.com/GOVCERT-LU/eml_parser/commit/746a69f86443eb0b6a47f77db3cfe727
- https://github.com/GOVCERT-LU/eml_parser/pull/90
- https://github.com/GOVCERT-LU/eml_parser/releases/tag/v3.0.2
- https://github.com/GOVCERT-LU/eml_parser/security/advisories/GHSA-g7gc-gmgp-wgqg
FAQ
What is CVE-2026-55620?
CVE-2026-55620 is a vulnerability with a CVSS score of 7.5 (HIGH). 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 em...
How severe is CVE-2026-55620?
CVE-2026-55620 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-55620?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.