CVE-2026-73629

Serendipity before 2.6.0 SSRF via hex IPv4 and IPv6 addresses

8.4 High

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.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: Low
User interaction: None

What an attacker can affect

Confidentiality: High
Integrity: Low
Availability: None

Exploit likelihood

0.32%Up 0.1 points since Aug 14, 2026

What each source reports

CVE List Score used 8.4

Serendipity before 2.6.0 SSRF via hex IPv4 and IPv6 addresses

Record: CVE-2026-73629
CVSS 4.0: 8.4 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:L/VA:N/SC:H/SI:L/SA:N
CVSS 3.1: 8.5 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N
Weakness: CWE-918
Updated: 2026-11-02

EUVDEUVD-2026-57798 8.4

Record: EUVD-2026-57798
CVSS 4.0: 8.4 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:L/VA:N/SC:H/SI:L/SA:N
Updated: 2026-11-02

GitHub AdvisoriesGHSA-fh9h-cxrw-2xj2 8.4

Serendipity before 2.6.0 contains a server-side request forgery vulnerability in the...

Record: GHSA-fh9h-cxrw-2xj2
CVSS 4.0: 8.4 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:L/VA:N/SC:H/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1: 8.5 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N
Weakness: CWE-918
Updated: 2026-11-02

NVD 8.4

Record: CVE-2026-73629
CVSS 4.0: 8.4 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:L/VA:N/SC:H/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1: 8.5 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N
Weakness: CWE-918
Updated: 2026-11-02

OSV 8.4

Serendipity before 2.6.0 SSRF via hex IPv4 and IPv6 addresses

Record: CVE-2026-73629
CVSS 4.0: 8.4 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:L/VA:N/SC:H/SI:L/SA:N
Weakness: CWE-918
Updated: 2026-11-02

Affected products

s9y serendipity

History

History
Recorded	Changed	Sources
Nov 2, 2026	first indexed	CVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-73629 is a high vulnerability (CVSS 8.4) in S9y Serendipity, published August 13, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.32%, the 25th percentile. No source names a fixed version.