CVE-2026-13707 — Session fixation attacks on improperly configured OAuth 1.0a tools
Session fixation vulnerability in Wikimedia Foundation OAuth. This vulnerability is associated with program files src/Backend/MWOAuthServer.Php. This issue affects OAuth: from * through 1.46.0, 1.45.4, 1.44.6, 1.43.9.
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 (high)+6
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 (Mediawiki Mediawiki, The Wikimedia Foundation OAuth).
- 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 (authentication), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Mediawiki | Mediawiki | ≥ 1.43.0 and < 1.43.9≥ 1.44.0 and < 1.44.6≥ 1.45.0 and < 1.45.4version 1.46.0-rc0 | Vulnerable | NIST National Vulnerability Database |
| The Wikimedia Foundation | OAuth | ≤ 1.46.0, 1.45.4, 1.44.6, 1.43.9 | 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 |
|---|---|---|---|---|---|
| 0.0 | CVSS 4.0 | None | — | — | c4f26cc8-17ff-4c99-b5e2-38fc1793eacc via NIST National Vulnerability Database |
| 0.0 | CVSS 4.0 | None | — | — | wikimedia-foundation via CVE Program (cve.org) e CISA ADP |
| 7.6 | CVSS 3.1 | High | 2.1 | 5.5 | nvd@nist.gov via NIST National Vulnerability Database |
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:L (score shown at the top: nvd@nist.gov) 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).
- Review authentication logs: logins without MFA, anomalous sessions and recently created accounts.
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · wikimedia foundation/oauth
- SSVC assessment updated
- Record published
- CVSS changed · 7.6
- Source status changed · → Analyzed
- 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
1 on the record
Elsewhere on this site
Related CVEs (same products)
- Medium CVE-2026-58517 Blocked users can create and edit WikiLambda objects Jul 1, 2026
- Medium CVE-2026-14358 Stored XSS in Wikimedia Chart pie tooltip via Data:*.tab field title Jul 1, 2026
- Medium CVE-2026-58520 UrlShortener defaults to ineffective validation open to third-party redirects Jul 1, 2026
- High CVE-2026-8857 Full RCE using EasyTimeline Extension Jul 1, 2026
- Medium CVE-2026-58037 Core log entries for exceptions and XSS issues in log entry formatting code that may be caused by user-controlled input Jul 1, 2026
- Medium CVE-2026-58038 Stored XSS through javascript URLs in SVGs generated by EasyTimeline Jul 1, 2026
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-2026-13707 is "Session fixation attacks on improperly configured OAuth 1.0a tools", rated High. It affects Mediawiki (Mediawiki); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.6 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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