What happened
libcurl might in some circumstances reuse the wrong connection when asked to do an authenticated HTTP(S) request after a Negotiate-authenticated one, when both use the same host. libcurl features a pool of recent connections so that subsequent requests can reuse an existing connection to avoid overhead. When reusing a connection a range of criteria must be met. Due to a logical error in the code, a request that was issued by an application could wrongfully reuse an existing connection to the same server that was authenticated using different credentials. An application that first uses Negotiate authentication to a server with `user1:password1` and then does another operation to the same server asking for any authentication method but for `user2:password2` (while the previous connection is still alive) - the second request gets confused and wrongly reuses the same connection and sends the new request over that connection thinking it uses a mix of user1's and user2's credentials when it is in fact still using the connection authenticated for user1...
Affected versions
curl: 7.10.6 through before 8.14.2 (semver); 8.15.0 through before 8.16.1 (semver); 8.17.0 through before 8.20.0 (semver); e56ae1426cb7a0a4a427cf8d6099a821fdaae428 through before 33e43985b8f3b9e66691d06e70be0395849856cd (git); 8.19.0; 8.18.0; 8.17.0; 8.16.0; 8.15.0; 8.14.1; 8.14.0; 8.13.0; 8.12.1; 8.12.0; 8.11.1; 8.11.0; 8.10.1; 8.10.0; 8.9.1; 8.9.0; 8.8.0; 8.7.1; 8.7.0; 8.6.0; 8.5.0; 8.4.0; 8.3.0; 8.2.1; 8.2.0; 8.1.2; 8.1.1; 8.1.0; 8.0.1; 8.0.0; 7.88.1; 7.88.0; 7.87.0; 7.86.0; 7.85.0; 7.84.0; 7.83.1; 7.83.0; 7.82.0; 7.81.0; 7.80.0; 7.79.1; 7.79.0; 7.78.0; 7.77.0; 7.76.1; 7.76.0; 7.75.0; 7.74.0; 7.73.0; 7.72.0; 7.71.1; 7.71.0; 7.70.0; 7.69.1; 7.69.0; 7.68.0; 7.67.0; 7.66.0; 7.65.3; 7.65.2; 7.65.1; 7.65.0; 7.64.1; 7.64.0; 7.63.0; 7.62.0; 7.61.1; 7.61.0; 7.60.0; 7.59.0; 7.58.0; 7.57.0; 7.56.1; 7.56.0; 7.55.1; 7.55.0; 7.54.1; 7.54.0; 7.53.1; 7.53.0; 7.52.1; 7.52.0; 7.51.0; 7.50.3; 7.50.2; 7.50.1; 7.50.0; 7.49.1; 7.49.0; 7.48.0; 7.47.1; 7.47.0; 7.46.0; 7.45.0; 7.44.0; 7.43.0; 7.42.1; 7.42.0; 7.41.0; 7.40.0; 7.39.0; 7.38.0; 7.37.1; 7.37.0; 7.36.0; 7.35.0; 7.34.0; 7.33.0; 7.32.0; 7.31.0; 7.30.0; 7.29.0; 7.28.1; 7.28.0; 7.27.0; 7.26.0; 7.25.0; 7.24.0; 7.23.1; 7.23.0; 7.22.0; 7.21.7; 7.21.6; 7.21.5; 7.21.4; 7.21.3; 7.21.2; 7.21.1; 7.21.0; 7.20.1; 7.20.0; 7.19.7; 7.19.6; 7.19.5; 7.19.4; 7.19.3; 7.19.2; 7.19.1; 7.19.0; 7.18.2; 7.18.1; 7.18.0; 7.17.1; 7.17.0; 7.16.4; 7.16.3; 7.16.2; 7.16.1; 7.16.0; 7.15.5; 7.15.4; 7.15.3; 7.15.2; 7.15.1; 7.15.0; 7.14.1; 7.14.0; 7.13.2; 7.13.1; 7.13.0; 7.12.3; 7.12.2; 7.12.1; 7.12.0; 7.11.2; 7.11.1; 7.11.0; 7.10.8; 7.10.7; 7.10.6 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.