Vulnerability Database

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Total vulnerabilities in the database

Gitea has insecure default SSH settings — code.gitea.io/gitea

Insecure Default Initialization of Resource

Summary

The built-in SSH server currently advertises a number of key exchange, MAC, and host key algorithms that are considered weak or broken. The defaults should be tightened so a fresh installation passes a baseline SSH security audit out of the box.

Details

Running ssh-audit against a default deployment flags the following as fail:

  • Key exchange
    • ecdh-sha2-nistp256
    • ecdh-sha2-nistp384
    • ecdh-sha2-nistp521
  • MAC
    • hmac-sha1
  • Host key
    • ssh-rsa

Reproduction

docker run -it --rm positronsecurity/ssh-audit -p 2222 gitea.local

Impact

Default deployments expose algorithms that are known-weak or deprecated upstream. The current workaround requires manually setting several GITEA__server__SSH_SERVER_* variables, which most users will never do.

Workaround

[server] SSH_SERVER_KEY_EXCHANGES = curve25519-sha256, diffie-hellman-group14-sha256 SSH_SERVER_CIPHERS = [email protected], aes128-ctr, aes192-ctr, aes256-ctr, [email protected], [email protected] SSH_SERVER_MACS = [email protected], hmac-sha2-256

There is no exposed option to restrict host key algorithms, so ssh-rsa remains advertised.

Acceptance criteria

  • [ ] Default SSH_SERVER_KEY_EXCHANGES, SSH_SERVER_CIPHERS, and SSH_SERVER_MACS updated to the secure list above.
  • [ ] New SSH_SERVER_HOST_KEY_ALGORITHMS option added, with a default that excludes ssh-rsa.
  • [ ] Documentation updated to reflect the new defaults.
  • [ ] ssh-audit against a fresh install reports no [fail] entries.
  • Published: Apr 22, 2026
  • Updated: Apr 23, 2026
  • GHSA: GHSA-3m6q-h5gj-7mrw
  • Severity: Medium
  • Exploit:
  • CISA KEV:

No technical information available.

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