CVE-2026-11856: 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 secon

criticalCVSS 9.8CVE-2026-11856

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.

Details

Source: NVD Recent CVEs (US · database · site)
Severity: critical — CVSS 9.8
Published: 2026-07-03
Last updated: 2026-07-07
Exploitation: Not in CISA KEV at last sync

Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-11856

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Moderate exploitation riskCVE-2026-118561.1% 30-day exploitation probability. Patch within normal cadence, watch for KEV listing. Riskier than 61% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-11856	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

medium[UPDATE] [medium] cURL: Multiple vulnerabilitiescert-bund
mediumCVE-2026-11856: cross-origin Digest auth state leakmsrc
unknownMultiple vulnerabilities in cURL and libcurl (June 24, 2026)cert-fr-avis

CVE-2026-11856: 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 secon

Details

Exploitation outlook

Referenced CVEs

Same CVEs, other sources

More from NVD Recent CVEs

CVE-2026-11856: 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 secon