CVE-2026-9547 — SSH improper host validation

Description (CNA)

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.

Affected (CNA)

Vendor / product	Versions
curl / curl	affected 7.69.0 before 8.14.2; affected 8.15.0 before 8.16.1; affected 8.17.0 before 8.20.1
curl / curl	affected 507cf6a13db0375eadd4655b4c64710db29e9cf2 before 0b8dbbc63c98777e4584cb9fbd71df3464008ad1
curl / curl	affected 8.20.0; affected 8.19.0; affected 8.18.0; affected 8.17.0; affected 8.16.0; affected 8.15.0; affected 8.14.1; affected 8.14.0; affected 8.13.0; affected 8.12.1; affected 8.12.0; affected 8.11.1; affected 8.11.0; affected 8.10.1; affected 8.10.0; affected 8.9.1; affected 8.9.0; affected 8.8.0; affected 8.7.1; affected 8.7.0; affected 8.6.0; affected 8.5.0; affected 8.4.0; affected 8.3.0; affected 8.2.1; affected 8.2.0; affected 8.1.2; affected 8.1.1; affected 8.1.0; affected 8.0.1; affected 8.0.0; affected 7.88.1; affected 7.88.0; affected 7.87.0; affected 7.86.0; affected 7.85.0; affected 7.84.0; affected 7.83.1; affected 7.83.0; affected 7.82.0; affected 7.81.0; affected 7.80.0; affected 7.79.1; affected 7.79.0; affected 7.78.0; affected 7.77.0; affected 7.76.1; affected 7.76.0; affected 7.75.0; affected 7.74.0; affected 7.73.0; affected 7.72.0; affected 7.71.1; affected 7.71.0; affected 7.70.0; affected 7.69.1; affected 7.69.0

CWE

CWE-297

References

ADP enrichment

CISA-ADP

No English description supplied.

https://hackerone.com/reports/3751712