Is CVE-2026-11856 in the CISA KEV catalog?

No. CVE-2026-11856 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the EPSS score for CVE-2026-11856?

CVE-2026-11856 has an EPSS score of 0.25% (16th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-11856?

Upgrade curl on debian unstable to 8.21.0~rc3-1 or later.

CVE & CISA-KEV Catalog

CVE-2026-11856

UNSCORED

NVD

Description

Successfully using libcurl to do a transfer to a specific HTTP origin (`hostA`) with **Digest** authentication and then changing the origin to a different one (`hostB`) for a second transfer, reusing the same handle, makes libcurl wrongly pass on the `Authorization:` header field meant for `hostA`, to `hostB`.

How to fix

Remediation Available

curlDebian

Fixed in:8.21.0~rc3-1CVE-2026-11856

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3.1 Vector

No CVSS vector data available.

Exploit Intelligence

0.25%probability of exploitation in 30 days

16thpercentile

Low risk: more likely to be exploited than 16% of all known CVEs.

References

Other references3

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-07-03.