libcurl would reuse a previously created connection even when some mTLS config related option had been changed that should have prohibited reuse.
libcurl keeps previously used connections in a connection pool for subsequent transfers to reuse if one of them matches the setup. However, some TLS settings related to client certificates were left out from the configuration match checks, making them match too easily. In particular options related to the private key.
Weakness
The authentication algorithm is sound, but the implemented mechanism can be bypassed as the result of a separate weakness that is primary to the authentication error.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Curl | Haxx | 7.7 (including) | 8.21.0 (excluding) |
| Red Hat Enterprise Linux 10 | RedHat | curl-0:8.12.1-4.el10_2.6 | * |
| Red Hat Enterprise Linux 10.0 Extended Update Support | RedHat | curl-0:8.12.1-1.el10_0.10 | * |
| Red Hat Hardened Images | RedHat | curl-main-8.21.0-0.1.hum1 | * |
| Red Hat Hardened Images | RedHat | rust-main-1.96.1-1.hum1 | * |
| Curl | Ubuntu | devel | * |
| Curl | Ubuntu | esm-infra-legacy/trusty | * |
| Curl | Ubuntu | esm-infra-legacy/xenial | * |
| Curl | Ubuntu | esm-infra/bionic | * |
| Curl | Ubuntu | esm-infra/focal | * |
| Curl | Ubuntu | jammy | * |
| Curl | Ubuntu | noble | * |
| Curl | Ubuntu | questing | * |
| Curl | Ubuntu | resolute | * |
| Curl | Ubuntu | upstream | * |