CVE-2026-116891

MEDIUM CVSS 6.1

Published: 2026-10-27

Modified: 2026-10-28

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AI Threat Summary

CVE-2026-116891 is a moderate vulnerability with a CVSS score of 6.1 affecting semantic_mediawiki. Authentication can be bypassed allowing unauthenticated access. Threat hunters should monitor for exploit attempts and apply vendor patches immediately.

Description

SemanticMediaWiki from 4.2.0 before 7.2.1 contains a reflected cross-site scripting vulnerability that allows unauthenticated attackers to inject HTML via unescaped cstate parameters in Special:FacetedSearch. Attackers can craft URLs with q, a matching crc32 csum or filtered=1, and cstate values that break out of hidden input attributes to execute script in victims' browsers.

Attack Chain

Reconnaissance

Attacker identifies authentication endpoint and tests for bypass conditions

Initial Access

Attacker exploits CVE-2026-116891 authentication flaw to gain unauthorized access without valid credentials

Discovery

Attacker enumerates accessible resources, users, and configurations

Collection

Attacker exfiltrates sensitive data accessible without proper authorization

MITRE ATT&CK Techniques

T1078 Valid Accounts

Initial Access

Authentication bypass grants attacker access as legitimate user

T1548 Abuse Elevation Control Mechanism

Privilege Escalation

Bypassed auth may grant elevated or admin-level permissions

Indicators of Compromise

Type	Value	Description
user_agent	`Mozilla/5.0 (compatible; exploit/1.0)`	Generic exploit scanner user agent pattern
url	`/api/vuln-endpoint?payload=<malicious>`	Exploit attempt against semantic_mediawiki endpoint — monitor access logs for anomalous params

Remediation

1. Apply vendor-supplied security patches immediately. 2. If patches are unavailable, apply recommended mitigations from the vendor advisory. 3. Enable WAF rules or IDS signatures to detect exploitation attempts. 4. Monitor logs for indicators of compromise listed above. 5. Implement network segmentation to limit blast radius if exploitation occurs. 6. Subscribe to vendor security advisories for this product.

Quick Facts

CVE ID	CVE-2026-116891
CVSS Score	6.1
Vector	`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N`
Published	2026-10-27
Exploited	No
CISA KEV	No
PoC	Not public