Gitea SSH certificate principal impersonation of other users
CVSS score
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EPSS probability
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Risk score
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Published
1 d ago
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Vulnerability description
CVE AI research
DayBreach AI Explanation
Verified against sourcesSources read
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Source agreement
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Evidence confidence
%55
Short explanation
Gitea resolved the principals of an SSH certificate by searching the content of all stored public keys instead of only principal keys [S0]. Under specific configuration conditions, this flaw can allow unauthorized authentication as another user [S0].
It allows unauthorized users to authenticate as the owner of another key through the HTTP signature API and the built-in SSH server [S0].
What should be done?
- Follow official vendor advisories to review updates [S0]
- Check Gitea release notes and security advisories for guidance [S0]
Chain of evidence and sources
Gitea, SSH sertifikalarının asıl yetkililerini ararken saklanan tüm genel anahtarların içeriğini taramaktadır [S0].
Kullanıcı sertifikası yetkilisi güvenildiğinde ve rastgele asıl yetkililere izin verildiğinde kimlik doğrulaması tehlikeye girebilir [S0].
Show the technical text from the sources
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.
Explanation produced with the local gemini-flash-lite-latest model. Numerical metrics and the KEV, patch and exploit statuses are not determined by AI.
IMPACT: Affected Products and Software
Affected Products
The following products are affected by CVE-2026-109553 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.
| ID | VENDOR | PRODUCT | ACTION |
|---|---|---|---|
| 1 | gitea | gitea | View |
RED HAT CSAF/VEX: Product Impact Check
SCORING: CVSS from Multiple Sources
CVSS Scores
The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.
| SCORE | VERSION | SEVERITY | VECTOR | SOURCE |
|---|---|---|---|---|
| The sources have not yet published a verified CVSS metric. | ||||
Patch and Remediation Guide
Solution & Remediation Advisory
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Public exploit and active exploitation status
Verified exploit intelligence
No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.
Weakness Classification and Attack Patterns (CWE & CAPEC)
CWE - Common Weakness Enumeration
While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-109553 is associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-109553 weaknesses.
Official Sources and Advisories
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