CVE-2026-73629

HIGH 8.5

Serendipity before 2.6.0 SSRF via hex IPv4 and IPv6 addresses

CVSS Score

8.5

EPSS Score

0.0%

EPSS Percentile

0th

Serendipity before 2.6.0 contains a server-side request forgery vulnerability in the serendipity_url_allowed() filter that fails to block hex-encoded IPv4 addresses, IPv6 literals, and link-local ranges. Authenticated users with adminImagesAdd permission can bypass the filter using alternate address formats to request internal services and retrieve response bodies through the public uploads directory.

CWE	CWE-918
Vendor	s9y
Product	serendipity
Published	Aug 13, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Changed

Confidentiality

High

Integrity

Low

Availability

None

Affected Versions

s9y / Serendipity

0 < 2.6.0

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/s9y/Serendipity/security/advisories/GHSA-2m48-gjj5-5x86 vulncheck.com: https://www.vulncheck.com/advisories/serendipity-before-ssrf-via-hex-ipv4-and-ipv6-addresses

Credits

🔍 riodrwn