Description
A flaw was found in libssh. The API function `ssh_get_hexa()` is vulnerable to a denial of service when processing zero-length input. This can be exploited remotely by an attacker during GSSAPI (Generic Security Service Application Program Interface) authentication if the server's logging verbosity is set to `SSH_LOG_PACKET (3)` or higher. Successful exploitation could lead to a self-Denial of Service of the per-connection daemon process.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Red Hat | Red Hat Enterprise Linux 10 | — | — |
| Red Hat | Red Hat Enterprise Linux 9 | — | — |
| Red Hat | Red Hat Hardened Images | — | — |
| Red Hat | Red Hat Enterprise Linux 6 | — | — |
| Red Hat | Red Hat Enterprise Linux 7 | — | — |
| Red Hat | Red Hat Enterprise Linux 8 | — | — |
| Red Hat | Red Hat OpenShift Container Platform 4 | — | — |
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 | 0.12.0-1 | — |
| Debian 13 | libssh | 0.11.5-0+deb13u1 | — |
| Debian 12 | libssh | 0.10.6-0+deb12u3 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 25.10 | libssh | 0.11.2-1ubuntu0.2 | USN-8051-1 |
| Ubuntu 24.04 LTS | libssh | 0.10.6-2ubuntu0.3 | USN-8051-1 |
| Ubuntu 22.04 LTS | libssh | 0.9.6-2ubuntu0.22.04.6 | USN-8051-1 |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 20.04 LTS | libssh | 0.9.3-2ubuntu2.5+esm3 | — |
| Ubuntu Pro 18.04 LTS | libssh | 0.8.0~20170825.94fa1e38-1ubuntu0.7+esm6 | — |
| Ubuntu Pro 16.04 LTS | libssh | 0.6.3-4.3ubuntu0.6+esm4 | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 10 | libssh +2 | 0.12.0-2.el10 | RHSA-2026:18160 |
| RHEL 9 | libssh +2 | 0.10.4-18.el9 | RHSA-2026:18683 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat Hardened Images 1 | libssh +2 | 0.12.0-1.1.hum1 | RHSA-2026:7067 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 10 | libssh +2 | 0.12.0-2.el10 | ALSA-2026:18160 |
| AlmaLinux 9 | libssh +2 | 0.10.4-18.el9 | ALSA-2026:18683 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 10 | libssh | 0.12.0-2.el10 | RLSA-2026:18160 |
| Rocky Linux 9 | libssh | 0.10.4-18.el9 | RLSA-2026:18683 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | libssh | 0.9.8-150600.11.9.1 | SUSE-SU-2026:0779-1 |
| SLES 12 SP5 | libssh | 0.6.3-12.28.1 | SUSE-SU-2026:1344-1, SUSE-SU-2026:0778-1 |
Show 6 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLE Micro 6.1 | libssh | 0.10.6-slfo.1.1_4.1 | SUSE-SU-2026:20531-1 |
| SLE Micro 6.0 | libssh | 0.10.6-4.1 | SUSE-SU-2026:20524-1 |
| SLE Micro 5.5 | libssh | 0.9.8-150400.3.17.1 | SUSE-SU-2026:1565-1 |
| SLE Micro 5.4 | libssh | 0.9.8-150400.3.17.1 | SUSE-SU-2026:1565-1 |
| SLE Micro 5.3 | libssh | 0.9.8-150400.3.17.1 | SUSE-SU-2026:1565-1 |
| SLE Micro 5.2 | libssh | 0.9.8-150200.13.15.1 | SUSE-SU-2026:0567-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | libssh | 0.11.4-1.1 | openSUSE-SU-2026:10203-1 |
| openSUSE Leap 15.6 | libssh | 0.9.8-150600.11.9.1 | SUSE-SU-2026:0779-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | libssh | 0.12.0-r0 | — |
| Alpine v3.23 | libssh | 0.11.4-r0 | — |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | libssh +2 | 0.10.6-1.amzn2023.0.4 | ALAS2023-2026-1461 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | libssh | 0.10.6-7 | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 10 | libssh +2 | 0.12.0-2.el10 | ELSA-2026-18160 |
| Oracle Linux 9 | libssh +2 | 0.10.4-18.el9 | ELSA-2026-18683 |
Advisories 20
- ALSA-2026:18683 Moderate: libssh security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:18160 Moderate: libssh security update AlmaLinux Security Advisories · Oct 29, 2026
- WID-SEC-2026-0446 libssh: Mehrere Schwachstellen ermöglichen Manipulation von Dateien und DoS BSI CERT-Bund (WID) · Oct 20, 2026
- RHSA-2026:18683 Red Hat Security Advisory: libssh security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2026:18160 Red Hat Security Advisory: libssh security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2026:7067 Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update Red Hat Security Advisories (RHSA) · Oct 6, 2026
- ELSA-2026-18160 Moderate: libssh security update (Oracle Linux 10) Oracle Linux Security Advisories (ELSA) · Jul 8, 2026
- ELSA-2026-18683 Moderate: libssh security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Jun 12, 2026
- RLSA-2026:18160 Moderate: libssh security update Rocky Linux Security Advisories · May 29, 2026
- RLSA-2026:18683 Moderate: libssh security update Rocky Linux Security Advisories · May 28, 2026
- USN-8051-1 libssh vulnerabilities Ubuntu Security Notices (USN) · May 14, 2026
- SUSE-SU-2026:1565-1 Security update for libssh SUSE / openSUSE Security Updates · Apr 24, 2026
- SUSE-SU-2026:1344-1 Security update for libssh SUSE / openSUSE Security Updates · Apr 16, 2026
- openSUSE-SU-2026:10203-1 libssh-config-0.11.4-1.1 on GA media SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2026:20524-1 Security update for libssh SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2026:20531-1 Security update for libssh SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2026:0567-1 Security update for libssh SUSE / openSUSE Security Updates · Mar 23, 2026
- ALAS2023-2026-1461 Important: libssh security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Mar 5, 2026
- SUSE-SU-2026:0779-1 Security update for libssh SUSE / openSUSE Security Updates · Mar 4, 2026
- SUSE-SU-2026:0778-1 Security update for libssh SUSE / openSUSE Security Updates · Mar 4, 2026
References
- RHSA-2026:18160 vendor-advisory
- RHSA-2026:18683 vendor-advisory
- RHSA-2026:7067 vendor-advisory
- https://access.redhat.com/security/cve/CVE-2026-0966 vdb-entry
- RHBZ#2433121 issue-tracking
- https://www.libssh.org/2026/02/10/libssh-0-12-0-and-0-11-4-security-releases/