Vulnerability · Published Oct 20, 2026 · Assigned by curl
CVE-2026-86415auto client cert connection reuse mixup
High 7.5
In plain English
A high-severity security flaw in curl from curl. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 36% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
libcurl's connection cache match function never considers the automatic client certificate option, so a cached, already authenticated Schannel connection can be handed to a transfer that got redirected to a different origin, even though the code explicitly switched off the auto client cert option for that transfer to prevent exactly this.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.23 | curl | 8.23.0-r0 | ALPINE-CVE-2026-86415 |
| Alpine:v3.24 | curl | 8.23.0-r0 | ALPINE-CVE-2026-86415 |
| Debian:14 | curl | no fix listed | DEBIAN-CVE-2026-86415 |
Affected products (as reported)
Weakness: CWE-201 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N