Read the docs
TI-2026-51713 Aliases CVE-2026-73629GHSA-fh9h-cxrw-2xj2

Serendipity before 2.6.0 SSRF via hex IPv4 and IPv6 addresses

Priority LOW 36CWE-918Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
—
Confidentiality · integrity · availability
High · Low · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

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 adminImagesAdd permission can bypass the filter using alternate address formats to request internal services and retrieve response bodies through the public uploads directory.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.0032 25th percentileScored 2026-11-07
Fix Fixed Serendipity (s9y): 2.6.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
s9ySerendipitybefore 2.6.02.6.0Patch availableCNA
  • Serendipity Vendors9y Affected before 2.6.0 Fixed in 2.6.0 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:s9y:serendipity:*:*:*:*:*:*:*:*——s9y
  • cpe:2.3:a:s9y:serendipity:*:*:*:*:*:*:*:* Versions — — ·s9y

Remediation

  • Fix · CNA Serendipity (s9y) Fixed in 2.6.0

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-73629
  2. 2026-10-03 Alias added: GHSA-fh9h-cxrw-2xj2

References

Advisory 1

  • TI-2026-47647 Serendipity < 2.6.1 Authentication Bypass via Username Collision CVSS 4.0HIGH 8.7
  • TI-2023-30216 Serendipity 2.4.0 Authenticated Remote Code Execution via File Upload CVSS 4.0HIGH 8.7
  • TI-2024-38379 Serendipity 2.5.0 Remote Code Execution via Authenticated Media Upload CVSS 4.0HIGH 8.6
  • TI-2026-28827 Serendipity: Host Header Injection leads to SMTP header injection via unvalidated HTTP_HOST CVSS 3.1HIGH 7.2
  • TI-2026-28819 Serendipity: Host Header Injection enables authentication cookie scoping to an attacker-controlled domain CVSS 3.1MEDIUM 6.9
  • TI-2026-51712 Serendipity 2.3.5 Reflected XSS via search clean-URL route CVSS 4.0MEDIUM 5.3
See all 64 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences