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CVE-2026-39376

CVE-2026-39376 · FastFeedParser has an infinite redirect loop DoS via meta-refresh chain

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

FastFeedParser is a high performance RSS, Atom and RDF parser. Prior to 0.5.10, when parse() fetches a URL that returns an HTML page containing a <meta http-equiv="refresh"> tag, it recursively calls itself with the redirect URL — with no depth limit, no visited-URL deduplication, and no redirect count cap. An attacker-controlled server that returns an infinite chain of HTML meta-refresh responses causes unbounded recursion, exhausting the Python call stack and crashing the process. This vulnerability can also be chained with the companion SSRF issue to reach internal network targets after bypassing the initial URL check. This vulnerability is fixed in 0.5.10.

CVSS 7.5 · High · EPSS 0.3% · Fix available

Published
Updated

Stack: python

Affected products and versions

  • fastfeedparser

    Versions
    • < 0.5.10: Affected

    No fix published

  • fastfeedparser PyPI

    Versions
    • 0.1.0
    • 0.2.0
    • 0.2.1
    • 0.2.2
    • 0.3.0
    • 0.3.1
    • 0.3.2
    • 0.3.3
    • 0.3.4
    • 0.3.5
    • 0.3.7
    • 0.3.8
    • 0.3.9
    • 0.4.0
    • 0.4.1
    • 0.4.2
    • 0.4.3
    • 0.4.4
    • 0.4.5
    • 0.4.6
    • 0.4.7
    • 0.4.8
    • 0.4.9
    • 0.5.0
    • 0.5.1
    • 0.5.2
    • 0.5.3
    • 0.5.4
    • 0.5.5
    • 0.5.6
    • 0.5.7
    • 0.5.8
    • 0.5.9
    Affected ranges
    • ECOSYSTEM: < 0.5.10

    Update to 0.5.10

Original sources

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