CVE-2026-86412: server-set cookie erases cookie jar

Severity: high (CVSS 8.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.8% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-20 · updated 2026-10-29
Weakness: CWE-754

Description

A remote HTTP server can set a cookie that curl accepts and writes to a Netscape cookie jar but cannot reload. On the next invocation using the same path for `--cookie` and `--cookie-jar`, curl fails before connecting, then the cleanup procedure replaces the jar with an empty file, deleting cookies for unrelated domains.

Affected products

curl: from 8.22.0 through 8.22.0; from 8.21.0 through 8.21.0; from 8.20.0 through 8.20.0; from 8.19.0 through 8.19.0; from 8.18.0 through 8.18.0

References

https://curl.se/docs/CVE-2026-86412.html
https://curl.se/docs/CVE-2026-86412.json
https://hackerone.com/reports/3973201
https://hackerone.com/reports/3973201

Get alerted when CVE-2026-86412 or the next vulnerability affects your stack