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TI-2026-28362 Aliases CVE-2026-39376GHSA-4gx2-pc4f-wq37

FastFeedParser has an infinite redirect loop DoS via meta-refresh chain

Priority HIGH 72CWE-674Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-674.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00341 27th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed fastfeedparser (kagisearch): 0.5.10fastfeedparser (PyPI): 0.5.10

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
kagisearchfastfeedparserbefore 0.5.100.5.10Patch availableCNA
—fastfeedparser (PyPI)before 0.5.100.5.10Patch availableGHSA-4gx2-pc4f-wq37
  • fastfeedparser Vendorkagisearch Affected before 0.5.10 Fixed in 0.5.10 Patch available CNA
  • fastfeedparser (PyPI) Vendor— Affected before 0.5.10 Fixed in 0.5.10 Patch available GHSA-4gx2-pc4f-wq37

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:kagi:fastfeedparser:*:*:*:*:*:python:*:*before 0.5.10VulnerableKagi
  • cpe:2.3:a:kagi:fastfeedparser:*:*:*:*:*:python:*:* Versions before 0.5.10 Vulnerable ·Kagi

Remediation

  • Fix · CNA fastfeedparser (kagisearch) Fixed in 0.5.10
  • Fix · GHSA-4gx2-pc4f-wq37 fastfeedparser (PyPI) Fixed in 0.5.10 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-39376
  2. 2026-10-03 Alias added: GHSA-4gx2-pc4f-wq37

References

Exploit 1

Advisory 1

Other 2

  • TI-2026-61597 kagisearch smallweb Query String Rendering sw.py index cross site scripting CVSS 4.0MEDIUM 5.3

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences