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-2026-9547

CVE-2026-9547HIGH

curl curl — SSH improper host validation

  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   N   H   N   N  U  H  H  N    7.4   .0051   41.2     —

AFFECTED
  Product  Versions                                    Fixed
  curl     7.69.0 –                                    —
  curl     507cf6a13db0375eadd4655b4c64710db29e9cf2 –  —
  curl     8.20.0 –                                    —

TIMELINE
  May 26  Reserved by curl
  Jul 3   EXPLOIT PUBLISHED — CVE-2026-9547 (curl). Public exploit reference added.
  Jul 3   Published (CNA: curl)
  Sep 15  EXPLOIT PUBLISHED — CVE-2026-9547 (curl). Public exploit reference added.

CWE-297 · CNA: curl · CVSS v3.1 · 3 references · NVD status: Modified

Description

When a libcurl-based application performs transfers via `SCP://` or `SFTP://` and utilizes the `CURLOPT_SSH_KEYFUNCTION` callback, it may silently accept an untrusted server. This vulnerability occurs when a server presents a host key type that does not match the specific key type already recorded for that host in the `known_hosts` file. Instead of rejecting the mismatch, the callback mechanism fails to properly enforce the restriction, allowing the connection to succeed without warning and risking a potential man-in-the-middle attack.

Lifecycle

Complete event history — 4 events, chronological
Date	Event	Detail
May 26, 2026	Reserved	Reserved by curl
July 3, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2026-9547 (curl). Public exploit reference added.
July 3, 2026	Published	Published (CNA: curl)
September 15, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2026-9547 (curl). Public exploit reference added.

Affected

Affected products and packages — 3 rows
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
curl	curl	—	7.69.0	—
curl	curl	—	507cf6a13db0375eadd4655b4c64710db29e9cf2	—
curl	curl	—	8.20.0	—

Weaknesses

CWE-297

References (3)

https://curl.se/docs/CVE-2026-9547.html [Patch, Vendor Advisory]
https://curl.se/docs/CVE-2026-9547.json [Vendor Advisory]
https://hackerone.com/reports/3751712 [Exploit, Issue Tracking, Third Party Advisory]

Authoritative record: CVE-2026-9547 at cve.org

Vendors: curl

Weaknesses: CWE-297

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-9547 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.