---
id: CVE-2026-73629
title: >-
  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
summary: >-
  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
  adminIma…
severity: high
cvss: 8.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N'
cwe:
  - CWE-918
published: '2026-08-13'
updated: '2026-09-09'
sourceUpdated: '2026-09-09T20:35:08.537'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-73629'
references:
  - url: 'https://github.com/s9y/Serendipity/security/advisories/GHSA-2m48-gjj5-5x86'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/serendipity-before-ssrf-via-hex-ipv4-and-ipv6-addresses
    label: disclosure@vulncheck.com
tags:
  - nvd
epss: 0.00189
epssPercentile: 0.08723
ingestedAt: '2026-09-09T21:22:45.533Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.