CVE-2026-67350 — Serendipity < 2.6.1 Open Redirect via exit.php
Serendipity before 2.6.1 contains an open redirect vulnerability in exit.php that allows unauthenticated attackers to redirect users to arbitrary external sites by supplying a malicious Base64-encoded url parameter when the Track Exits plugin is configured with commentredirection set to s9y. Attackers can craft trusted-looking URLs leveraging the legitimate blog domain to conduct phishing, deliver malware, or bypass URL reputation filters.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- Technical severity (medium)+3
- CISA SSVC: exploitation "poc"+5
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
CISA SSVC assessment CISA
Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (S9y Serendipity).
- The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
- No fix documented in the sources: reduce exposure and monitor the vendor advisory.
- Exploitation requires user interaction: tighten email/web filtering and warn affected users.
- Search available logs for exploit probes matching the vulnerability class (open redirect), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| S9y | Serendipity | < 2.6.1 | Vulnerable | CVE Program (cve.org) e CISA ADP |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 2.1 | CVSS 4.0 | Low | — | — | disclosure@vulncheck.com via NIST National Vulnerability Database |
| 2.1 | CVSS 4.0 | Low | — | — | VulnCheck via CVE Program (cve.org) e CISA ADP |
| 4.3 | CVSS 3.1 | Medium | 2.8 | 1.4 | disclosure@vulncheck.com via NIST National Vulnerability Database |
| 4.3 | CVSS 3.1 | Medium | — | — | VulnCheck via CVE Program (cve.org) e CISA ADP |
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N (score shown at the top: disclosure@vulncheck.com) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · s9y/serendipity
- SSVC assessment updated
- Record published
- CVSS changed · 4.3
- Source status changed · → Deferred
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× Official description updated · Oct 15, 2026 – Oct 15, 2026
References
2 on the record
Elsewhere on this site
Related CVEs (same products)
- Medium CVE-2026-73628 Serendipity 2.3.5 Reflected XSS via search clean-URL route Aug 13, 2026
- High CVE-2026-73629 Serendipity before 2.6.0 SSRF via hex IPv4 and IPv6 addresses Aug 13, 2026
- Medium CVE-2026-39963 Serendipity: Host Header Injection enables authentication cookie scoping to an attacker-controlled domain Apr 15, 2026
- High CVE-2026-39971 Serendipity: Host Header Injection leads to SMTP header injection via unvalidated HTTP_HOST Apr 15, 2026
- Medium CVE-2023-53932 Serendipity 2.4.0 Stored Cross-Site Scripting via Admin Entry Creation Dec 17, 2025
- High CVE-2023-53933 Serendipity 2.4.0 Authenticated Remote Code Execution via File Upload Dec 17, 2025
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No FIRST EPSS score.
- No fixed version, patch or mitigation documented.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2026-67350 is "Serendipity < 2.6.1 Open Redirect via exit.php", rated Medium. It affects Serendipity (S9y); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 4.3 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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