CVE-2026-39828
Published: 22 May 2026
Summary
CVE-2026-39828 is a medium-severity Improper Certificate Validation (CWE-295) vulnerability in Golang Crypto. Its CVSS base score is 6.3 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique SSH (T1021.004); ranked at the 12.6th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-31394
Vulnerability details
When an SSH server authentication callback returned PartialSuccessError with non-nil Permissions, those permissions were silently discarded, potentially dropping certificate restrictions such as force-command after a second factor succeeded. Returning non-nil Permissions with PartialSuccessError now results in a connection error.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Vuln allows bypassing SSH cert permission restrictions (e.g. force-command) post-MFA, directly enabling unauthorized remote SSH access and arbitrary command execution.
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Forces removal or modification of permissions no longer required after reassignment, preventing improper preservation of old access rights.
When certificates are used to establish component provenance, the control requires correct certificate validation procedures.
Mandates approved trust anchors and issuance policies, directly preventing acceptance of unvalidated or untrusted certificates.
Correct system time is required for proper enforcement of certificate notBefore/notAfter dates and time-based revocation checks.