Unbounded Recursion Vulnerability in FastFeedParser by Kagisearch
CVE-2026-39376

7.5HIGH

Key Information:

Vendor

Kagisearch

Vendor
CVE Published:
7 April 2026

Badges

๐Ÿ‘พ Exploit Exists๐ŸŸก Public PoC

What is CVE-2026-39376?

The FastFeedParser library, utilized for parsing RSS, Atom, and RDF feeds, is prone to an unbounded recursion vulnerability. In versions prior to 0.5.10, the parse() function can be exploited when it encounters a redirect URL that invokes HTML meta-refresh tags. This flaw allows an attacker to create an infinite loop of redirects, leading to excessive consumption of resources that can crash the Python process. Additional concerns arise as this vulnerability can be exploited alongside a Server-Side Request Forgery (SSRF) issue to target internal networks, potentially bypassing initial security checks.

Affected Version(s)

fastfeedparser < 0.5.10

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

References

CVSS V3.1

Score:
7.5
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • ๐ŸŸก

    Public PoC available

  • ๐Ÿ‘พ

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

.