CVE-2026-109553 Vulnerability Analysis & Exploit Details

CVE-2026-109553
Vulnerability Scoring

Analysis In Progress

Attack Complexity Details

Attack Complexity:
Attack Complexity Analysis In Progress
Attack Vector:
Attack Vector Under Analysis
Privileges Required: None
No authentication is required for exploitation.
Scope:
Impact is confined to the initially vulnerable component.
User Interaction: None
No user interaction is necessary for exploitation.

CVE-2026-109553 Details

Status: Received on 18 Oct 2026, 19:16 UTC

Published on: 18 Oct 2026, 19:16 UTC

CVSS Release:

CVE-2026-109553 Vulnerability Summary

CVE-2026-109553: Gitea resolved the principals of an SSH certificate by searching the content of all stored public keys instead of only principal keys. When Gitea trusts a user certificate authority (`SSH_TRUSTED_USER_CA_KEYS`) and accepts arbitrary principals (`SSH_AUTHORIZED_PRINCIPALS_ALLOW=anything`), a user could register another user's public key line as their own principal, or a holder of a certificate signed by that authority could list it, and then authenticate as the owner of that key through the HTTP signature API and the built-in SSH server. Instances that do not trust a user certificate authority are not affected.

Assessing the Risk of CVE-2026-109553

Access Complexity Graph

The exploitability of CVE-2026-109553 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).

Exploitability Analysis for CVE-2026-109553

No exploitability data is available for CVE-2026-109553.

Understanding AC and PR

A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.

Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.

Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.

CVSS Score Breakdown Chart

Above is the CVSS Sub-score Breakdown for CVE-2026-109553, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.

CIA Impact Analysis

Below is the Impact Analysis for CVE-2026-109553, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.

Confidentiality: None
CVE-2026-109553 does not compromise confidentiality.
Integrity: None
CVE-2026-109553 does not impact data integrity.
Availability: None
CVE-2026-109553 does not affect system availability.

CVE-2026-109553 References

External References

CWE Common Weakness Enumeration

Unknown

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