Description
A flaw was found in libssh. Logic errors in automatic certificate-based public key authentication can cause libssh clients to loop indefinitely when configured certificates are missing or repeatedly rejected by a server, leading to denial of service.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Red Hat | Red Hat Enterprise Linux 10 | — | — |
| Red Hat | Red Hat Hardened Images | — | — |
| Red Hat | Red Hat Enterprise Linux 8 | — | — |
| Red Hat | Red Hat Enterprise Linux 9 | — | — |
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 | libssh | 0.12.1-1 | — |
| Debian 13 | libssh | 0.11.5-0+deb13u1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.04 LTS | libssh | 0.11.3-1ubuntu2.1 | USN-8699-1 |
| Ubuntu 24.04 LTS | libssh | 0.10.6-2ubuntu0.5 | USN-8699-1 |
| Ubuntu 22.04 LTS | libssh | 0.9.6-2ubuntu0.22.04.8 | USN-8699-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 10 | libssh +2 | 0.12.0-3.el10_2 | RHSA-2026:55855 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat Hardened Images 1 | libssh +2 | 0.12.1-4.hum1 | RHSA-2026:42922 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 10 | libssh +2 | 0.12.0-3.el10_2 | ALSA-2026:55855 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 10 | libssh | 0.12.0-3.el10_2 | RLSA-2026:55855 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 16.0 | libssh | 0.11.5-160000.1.1 | SUSE-SU-2026:22956-1, SUSE-SU-2026:22948-1 |
| SLES 16.0 | libssh | 0.11.5-160000.1.1 | SUSE-SU-2026:22956-1, SUSE-SU-2026:22948-1 |
| SLE Micro 6.2 | libssh | 0.11.5-160000.1.1 | SUSE-SU-2026:22940-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | libssh | 0.11.5-1.2 | openSUSE-SU-2026:11377-1 |
| openSUSE Leap 16.0 | libssh | 0.11.5-160000.1.1 | openSUSE-SU-2026:21444-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | libssh | 0.12.1-r0 | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 10 | libssh +2 | 0.12.0-3.el10_2 | ELSA-2026-55855 |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | libssh +1 | 0.12.1-r0 | — |
Advisories 12
- ALSA-2026:55855 Important: libssh security update AlmaLinux Security Advisories · Oct 29, 2026
- WID-SEC-2026-2428 libssh: Mehrere Schwachstellen BSI CERT-Bund (WID) · Oct 22, 2026
- RHSA-2026:42922 Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update Red Hat Security Advisories (RHSA) · Oct 6, 2026
- RHSA-2026:55855 Red Hat Security Advisory: libssh security update Red Hat Security Advisories (RHSA) · Sep 2, 2026
- USN-8699-1 libssh vulnerabilities Ubuntu Security Notices (USN) · Aug 31, 2026
- RLSA-2026:55855 Important: libssh security update Rocky Linux Security Advisories · Aug 18, 2026
- ELSA-2026-55855 Important: libssh security update (Oracle Linux 10) Oracle Linux Security Advisories (ELSA) · Aug 17, 2026
- SUSE-SU-2026:22956-1 Security update for libssh SUSE / openSUSE Security Updates · Jul 29, 2026
- SUSE-SU-2026:22948-1 Security update for libssh SUSE / openSUSE Security Updates · Jul 29, 2026
- SUSE-SU-2026:22940-1 Security update for libssh SUSE / openSUSE Security Updates · Jul 29, 2026
- openSUSE-SU-2026:11377-1 libssh-config-0.11.5-1.1 on GA media SUSE / openSUSE Security Updates · Jul 27, 2026
- openSUSE-SU-2026:21444-1 Security update for libssh SUSE / openSUSE Security Updates · Jul 26, 2026
References
- RHSA-2026:42922 vendor-advisory
- RHSA-2026:55855 vendor-advisory
- https://access.redhat.com/security/cve/CVE-2026-59849 vdb-entry
- RHBZ#2498182 issue-tracking