Description
When libcurl uses libssh2 with a hashed `known_hosts` file, an unrelated
initial entry can cause host key validation to report a key *mismatch* as a
*missing* key to the `CURLOPT_SSH_KEYFUNCTION` callback.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| curl | curl | 8.22.0 – ≤ 8.22.0, 8.21.0 – ≤ 8.21.0, 8.20.0 – ≤ 8.20.0, 8.19.0 – ≤ 8.19.0, 8.18.0 – ≤ 8.18.0, 8.17.0 – ≤ 8.17.0, 8.16.0 – ≤ 8.16.0, 8.15.0 – ≤ 8.15.0, 8.14.1 – ≤ 8.14.1, 8.14.0 – ≤ 8.14.0, 8.13.0 – ≤ 8.13.0, 8.12.1 – ≤ 8.12.1, 8.12.0 – ≤ 8.12.0, 8.11.1 – ≤ 8.11.1, 8.11.0 – ≤ 8.11.0, 8.10.1 – ≤ 8.1… | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | curl | No fix yet | — |
| Debian 13 | curl | No fix yet | — |
| Debian 12 | curl | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | curl | 8.20.0-2ubuntu11.1 | USN-8927-2 |
| Ubuntu 26.04 LTS | curl | 8.18.0-1ubuntu2.8 | USN-8927-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat Hardened Images 1 | curl +3 | 8.23.0-0.1.hum1 | RHSA-2026:82895 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | curl | 8.23.0-1.1 | openSUSE-SU-2026:12150-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | curl | 8.23.0-r0 | — |
| Alpine v3.23 | curl | 8.23.0-r0 | — |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | curl +2 | 8.3.0-1.amzn2.0.14 | ALAS2-2026-4099 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | curl +4 | No fix yet | — |
Advisories 6
- WID-SEC-2026-3904 cURL: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 12, 2026
- ALAS2-2026-4099 Important: curl security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Nov 12, 2026
- USN-8927-1 curl vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
- USN-8927-2 curl vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
- RHSA-2026:82895 Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update Red Hat Security Advisories (RHSA) · Oct 18, 2026
- openSUSE-SU-2026:12150-1 curl-8.23.0-1.1 on GA media SUSE / openSUSE Security Updates · Oct 17, 2026