Reference page — cumulative record through Sunday, October 4, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2026-11856

CVE-2026-11856CRITICAL

curl curl — cross-origin Digest auth state leak

  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   N   L   N   N  U  H  H  H    9.8   .0069   51.0     —

AFFECTED
  Product  Versions                                    Fixed
  curl     7.10.6 –                                    —
  curl     334d78cd18a7310144383929bdcef34ffbf6159b –  —
  curl     8.20.0 –                                    —

TIMELINE
  Jun 10  Reserved by curl
  Jul 3   EXPLOIT PUBLISHED — CVE-2026-11856 (curl). Public exploit reference added.
  Jul 3   Published (CNA: curl)
  Sep 15  EXPLOIT PUBLISHED — CVE-2026-11856 (curl). Public exploit reference added.

CWE-294 · CNA: curl · CVSS v3.1 · 3 references · NVD status: Modified

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`.

Lifecycle

Complete event history — 4 events, chronological
Date	Event	Detail
June 10, 2026	Reserved	Reserved by curl
July 3, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2026-11856 (curl). Public exploit reference added.
July 3, 2026	Published	Published (CNA: curl)
September 15, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2026-11856 (curl). Public exploit reference added.

Affected

Affected products and packages — 3 rows
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
curl	curl	—	7.10.6	—
curl	curl	—	334d78cd18a7310144383929bdcef34ffbf6159b	—
curl	curl	—	8.20.0	—

Weaknesses

CWE-294

References (3)

https://curl.se/docs/CVE-2026-11856.html [Patch, Vendor Advisory]
https://curl.se/docs/CVE-2026-11856.json [Vendor Advisory]
https://hackerone.com/reports/3793260 [Exploit, Issue Tracking, Third Party Advisory]

Authoritative record: CVE-2026-11856 at cve.org

Vendors: curl

Weaknesses: CWE-294

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-11856 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Sunday, October 4, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.