CVE-2026-87861

UNKNOWN 0.0

cross-origin reuse of a Negotiate connection

CVSS Score

0.0

EPSS Score

0.0%

EPSS Percentile

0th

When using ambient user credentials, an HTTP request directed to one origin may be dispatched over a connection previously authenticated via Negotiate for a different origin, leaving the request's intended credentials unused.

Vendor	curl
Product	curl
Published	Oct 20, 2026

Stay Ahead of the Next One

Get instant alerts for curl curl

Be the first to know when new unknown vulnerabilities affecting curl curl are published — delivered to Slack, Telegram or Discord.

Get Free Alerts → Free · No credit card · 60 sec setup

Affected Versions

curl / curl

8.22.0 ≤ 8.22.0 8.21.0 ≤ 8.21.0

References

NVD ↗ CVE.org ↗ EPSS Data ↗

curl.se: https://curl.se/docs/CVE-2026-87861.json curl.se: https://curl.se/docs/CVE-2026-87861.html hackerone.com: https://hackerone.com/reports/3972094

Credits

Axel Mierczuk Stefan Eissing