CVE-2026-8458 — wrong reuse for different services

Affected: curl

libcurl might in some circumstances reuse the wrong connection when asked to do Negotiate-authenticated ones, even when they are set to use different "services".

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 services.

USN-8487-1 — curl vulnerabilities

Affected: Ubuntu:Pro:14.04:LTS: curl, Ubuntu:Pro:16.04:LTS: curl, Ubuntu:Pro:18.04:LTS: curl, Ubuntu:Pro:20.04:LTS: curl, Ubuntu:22.04:LTS: curl, Ubuntu:24.04:LTS: curl, Ubuntu:25.10: curl, Ubuntu:26.04:LTS: curl

Andrew Nesbitt discovered that curl could reuse an existing live connection during STARTTLS-based connection upgrades even when the TLS configuration did not match. A remote attacker could possibly use this issue to cause curl to use an unintended TLS configuration. (CVE-2026-8286)

Muhamad Arga Reksapati discovered that curl incorrectly reused connections for Negotiate-authenticated requests when different services were involved. A remote attacker could possibly use this issue to access resources authenticated for another service. This issue only affected Ubuntu 18.04 LTS, Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, Ubuntu 25.10, and Ubuntu 26.04 LTS. (CVE-2026-8458)

It was discovered that curl incorrectly handled cookie parsing in certain circumstances. A remote attacker could possibly use this issue to set cookies that would be transmitted to unrelated third-party domains. This issue only affected Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, Ubuntu 25.10, and Ubuntu 26.04 LTS. (CVE-2026-8924)

Joshua Rogers discovered that curl could double-free a GSASL context when handling SASL authentication. A remote attacker could possibly use this issue to cause a denial of service, or execute arbitrary code. This issue only affected Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, Ubuntu 25.10, and Ubuntu 26.04 LTS. (CVE-2026-8925)

Joshua Rogers discovered that curl could select the wrong password from a .netrc file when a username was sp…

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CVE-2026-8458 — wrong reuse for different services

USN-8487-1 — curl vulnerabilities