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TI-2026-51712 Aliases CVE-2026-73628GHSA-4g8w-wg6x-gvqc

Serendipity 2.3.5 Reflected XSS via search clean-URL route

Priority MEDIUM 57CWE-79Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Passive
Attack complexity
Low
Attack requirements
None
Impact type
Cross-site scripting
Confidentiality · integrity · availability
Low · Low · None
Fix status
No fix listed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-79.

Summary

Serendipity versions >= 2.3.5 and <= 2.6.0 contain a reflected cross-site scripting vulnerability in the search clean-URL route (/search/<term>). In include/functions_routing.inc.php serveSearch(), the sanitisation pipeline runs urldecode() after HTML-encoding, so a single URL-encoded HTML payload survives strip_tags() and htmlspecialchars() and is then decoded back into live HTML in the page. A crafted search link can execute arbitrary JavaScript in the victim's browser. Fixed in 2.6.1.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00263 18th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
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
s9ySerendipity2.3.5 – 2.6.0—No fix listedCNA
  • Serendipity Vendors9y Affected 2.3.5 – 2.6.0 Fixed in — No fix listed 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

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-73628
  2. 2026-10-03 Alias added: GHSA-4g8w-wg6x-gvqc

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-2023-30215 Serendipity 2.4.0 Stored Cross-Site Scripting via Admin Entry Creation CVSS 4.0MEDIUM 5.1
See all 64 →

Sources

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