CVE-2026-39376

7.5 HIGH
Published: April 07, 2026 Modified: April 14, 2026
View on NVD

Description

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.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://github.com/kagisearch/fastfeedparser/security/advisories/GHSA-4gx2-pc4f-wq37
Source: security-advisories@github.com
Exploit Vendor Advisory
https://github.com/kagisearch/fastfeedparser/security/advisories/GHSA-4gx2-pc4f-wq37
Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0
Exploit Vendor Advisory

2 reference(s) from NVD

Quick Stats

CVSS v3 Score
7.5 / 10.0
EPSS (Exploit Probability)
0.1%
16th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

kagi