CVE-2026-55369

MEDIUM CVSS 6.5
Published: 2026-10-28
Modified: 2026-10-28
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AI Threat Summary

CVE-2026-55369 is a moderate vulnerability with a CVSS score of 6.5 affecting the target software. Authentication can be bypassed allowing unauthenticated access. Threat hunters should monitor for exploit attempts and apply vendor patches immediately.

Description

Waline is a comment system with backend support. Prior to version 1.41.1, the login endpoint POST /api/token reads the email field from the request body without checking its type and passes it straight into the MongoDB storage query. When email is not a string (for example a JSON object such as {"$ne": null}), the MongoDB storage adapter's parseWhere silently DROPS the field rather than rejecting the request, producing an empty filter that matches ALL users. The endpoint then verifies the submitted password against the FIRST user returned (user[0]), which in Waline is the first-registered user — the site administrator. This is a PARTIAL authentication bypass, not a full one. The attacker still needs a valid password for that first user; this is not a zero-knowledge bypass and it does not disclose passwords. Its concrete effects are: (1) the email/identifier factor is removed for the administrator account, (2) user enumeration (a non-string email never fails the "no such user" branch), and (3) credential-stuffing amplification — an attacker can test a leaked or weak password against the administrator account without knowing the administrator's email. This issue has been patched in version 1.41.1.

Attack Chain
1
Reconnaissance

Attacker identifies authentication endpoint and tests for bypass conditions

2
Initial Access

Attacker exploits CVE-2026-55369 authentication flaw to gain unauthorized access without valid credentials

3
Discovery

Attacker enumerates accessible resources, users, and configurations

4
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 application 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-2026-55369
CVSS Score 6.5
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Published 2026-10-28
Exploited No
CISA KEV No
PoC Not public
References
External Resources
NVD Entry BleepingComputer The Hacker News