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CVE-2026-55620

CVE-2026-55620 · eml_parser: DoS via deeply nested parens in Received headers

This page contains facts from public vulnerability sources. Check the original advisory before updating.

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 7.5 · High · EPSS 0.6% · Fix available

Published
Updated

Stack: python

Affected products and versions

  • eml_parser

    Versions
    • < 3.0.2: Affected

    No fix published

  • eml-parser PyPI

    Versions
    • 0.9
    • 1.0
    • 1.1
    • 1.10
    • 1.11
    • 1.11.1
    • 1.11.2
    • 1.11.4
    • 1.11.5
    • 1.11.6
    • 1.11.7
    • 1.12.0
    • 1.13.0
    • 1.14.0
    • 1.14.1
    • 1.14.2
    • 1.14.3
    • 1.14.4
    • 1.14.5
    • 1.14.6
    • 1.14.7
    • 1.14.8
    • 1.15.0
    • 1.16.0
    • 1.17.0
    • 1.17.1
    • 1.17.2
    • 1.17.3
    • 1.17.4
    • 1.17.5
    • 1.3
    • 1.4
    • 1.5
    • 1.6
    • 1.7
    • 1.8
    • 1.9
    • 2.0.0
    • 2.0.1
    • 3.0.0
    • 3.0.1
    Affected ranges
    • ECOSYSTEM: < 3.0.2

    Update to 3.0.2

Original sources

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