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Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

CVE-2026-45695

High
9.8/10

Summary

Kopia's HTTP server, when started with `--without-password `, accepts unauthenticated requests to `/api/v1/repo/exists`. The handler forwards an attacker-supplied storage configuration to `blob.NewStorage`. For SFTP backends with `externalSSH: true`, that path constructs a process command line by splitting `sshArguments` on spaces and passes the result directly to `exec.CommandContext("ssh")`. An `-oProxyCommand=<cmd>` token in `sshArguments` causes OpenSSH to invoke `<cmd>` via `$SHELL -c` before any TCP connection is attempted, giving the requester arbitrary command execution as the Kopia process user. All versions prior to 0.23.0 are affected.

  • LOW
  • NETWORK
  • HIGH
  • UNCHANGED
  • NONE
  • NONE
  • HIGH
  • HIGH

CWE-78 - OS Command Injection

The OS command injection weakness (also known as shell injection) is a vulnerability which enables an attacker to run arbitrary OS commands on a server. This is done by modifying the intended downstream OS command and injecting arbitrary commands, enabling the execution of unauthorized OS commands. This has the potential to fully compromise the application along with all of its data, and, if the compromised process does not follow the principle of least privileges, it may compromise other parts of the hosting infrastructure as well. This weakness is listed as number ten in the 'CWE Top 25 Most Dangerous Software Weaknesses'.

References

Advisory Timeline

  • Published