boringproxy vulnerability

boringproxy through 0.10.0 contains a newline injection vulnerability that allows authenticated low-privileged users with tunnel-creation permission to inject arbitrary lines into the server account's SSH authorized_keys file by supplying a percent-encoded newline character in the domain parameter of the tunnel creation endpoint. Attackers can insert an unrestricted public key entry into authorized_keys to gain persistent shell access, and subsequently read cleartext credentials from the database file including all user tokens, tunnel private keys, and TLS certificates.

Published 5 Aug 2026Updated 24 Sep 20262 sources
CVSS 8.5

What happened

boringproxy through 0.10.0 contains a newline injection vulnerability that allows authenticated low-privileged users with tunnel-creation permission to inject arbitrary lines into the server account's SSH authorized_keys file by supplying a percent-encoded newline character in the domain parameter of the tunnel creation endpoint. Attackers can insert an unrestricted public key entry into authorized_keys to gain persistent shell access, and subsequently read cleartext credentials from the database file including all user tokens, tunnel private keys, and TLS certificates.

Affected versions

boringproxy: 0 through 0.10.0 (semver) Fixed: See vendor advisory.

Why it matters

Review the vendor advisory and exposure of the affected product to determine operational impact.

Detection & mitigation

  • Apply vendor-provided updates or mitigations.
  • Review affected product exposure and access logs.

Public PoC references

No public PoC reference has passed the current publication threshold.