curl vulnerability

Successfully using libcurl to do a transfer to a specific HTTP origin (`hostA`) with **Digest** authentication and then changing the origin to a different one (`hostB`) for a second transfer, reusing the same handle, makes libcurl wrongly pass on the `Authorization:` header field meant for `hostA`, to `hostB`.

Published 3 Jul 2026Updated 15 Sep 20266 sources
CVSS 9.8 ✓ VERIFIED REFERENCE

What happened

Successfully using libcurl to do a transfer to a specific HTTP origin (`hostA`) with **Digest** authentication and then changing the origin to a different one (`hostB`) for a second transfer, reusing the same handle, makes libcurl wrongly pass on the `Authorization:` header field meant for `hostA`, to `hostB`.

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 8.20.1 (semver); 334d78cd18a7310144383929bdcef34ffbf6159b through before 5c6b4880357ab3e72967c1c45cae0f96ffabc535 (git); 8.20.0; 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.

Public PoC references

RepositoryAuthorFirst seenReference
hackerone.comNVD reference2026-07-03Verified