CVE catalog
CVE-2026-59849
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 r
- Severity
- Medium · CVSS 6.7
CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H - Published
- Source
- [NVD] · [CVE record]
- EPSS
- 0.44% · Oct 25, 2026
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.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | libssh | sid | 0.12.2-1 | fixed |
| Debian | libssh | forky | 0.12.2-1 | fixed |
| Debian | libssh | trixie | 0.11.5-0+deb13u1 | fixed |
| Debian | libssh | trixie-security | 0.11.5-0+deb13u1 | fixed |
| Debian | libssh | bookworm | 0.10.6-0+deb12u2 | not affected |
| Debian | libssh | bookworm-security | 0.10.6-0+deb12u3 | not affected |
| Cpe | libssh | Not reported | Not reported | vulnerable |
| Cpe | libssh | Not reported | Not reported | unknown |
| Cpe | hardened_images | Not reported | Not reported | unknown |
| Cpe | enterprise_linux | Not reported | Not reported | unknown |
| Ubuntu | libssh | noble | 0.10.6-2ubuntu0.5 | fixed |
| Ubuntu | libssh-4 | noble | 0.10.6-2ubuntu0.5 | fixed |
| Ubuntu | libssh-dev | noble | 0.10.6-2ubuntu0.5 | fixed |
| Ubuntu | libssh-doc | noble | 0.10.6-2ubuntu0.5 | fixed |
| Ubuntu | libssh-gcrypt-4 | noble | 0.10.6-2ubuntu0.5 | fixed |
| Ubuntu | libssh-gcrypt-dev | noble | 0.10.6-2ubuntu0.5 | fixed |
| Cpe | enterprise_linux_for_els | Not reported | Not reported | unknown |
| Cpe | enterprise_linux_for_eus | Not reported | Not reported | unknown |
| Cpe | enterprise_linux_for_ibm_z_systems | Not reported | Not reported | unknown |
| Cpe | enterprise_linux_for_ibm_z_systems_els | Not reported | Not reported | unknown |
| Cpe | enterprise_linux_for_ibm_z_systems_eus | Not reported | Not reported | unknown |
| Cpe | enterprise_linux_for_power_little_endian | Not reported | Not reported | unknown |
| Cpe | enterprise_linux_for_power_little_endian_els | Not reported | Not reported | unknown |
| Cpe | enterprise_linux_for_power_little_endian_eus | Not reported | Not reported | unknown |
| Ubuntu | libssh | 26.04 | 0.11.2-1build1 | vulnerable |
| Ubuntu | libssh | 26.04 | 0.11.3-1 | vulnerable |
| Ubuntu | libssh | 26.04 | 0.11.3-1ubuntu1 | vulnerable |
| Ubuntu | libssh | 26.04 | 0.11.3-1ubuntu2 | vulnerable |
| Ubuntu | libssh | 26.04 | 0.11.3-1ubuntu2.1 | fixed |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | libssh | source | sid | 0.12.1-1 | not yet assigned | Not reported | [1142537] |
| Debian | libssh | source | forky | 0.12.1-1 | not yet assigned | Not reported | [1142537] |
| Debian | libssh | source | trixie | 0.11.5-0+deb13u1 | not yet assigned | Not reported | [1142537] |
| Debian | libssh | source | bookworm | Not affected | unimportant | Not reported | [1142537] |
| Ubuntu | libssh | deb | noble | 0.10.6-2ubuntu0.5 | Not reported | Not reported | Not reported |
| Ubuntu | libssh-4 | deb | noble | 0.10.6-2ubuntu0.5 | Not reported | Not reported | Not reported |
| Ubuntu | libssh-dev | deb | noble | 0.10.6-2ubuntu0.5 | Not reported | Not reported | Not reported |
| Ubuntu | libssh-doc | deb | noble | 0.10.6-2ubuntu0.5 | Not reported | Not reported | Not reported |
| Ubuntu | libssh-gcrypt-4 | deb | noble | 0.10.6-2ubuntu0.5 | Not reported | Not reported | Not reported |
| Ubuntu | libssh-gcrypt-dev | deb | noble | 0.10.6-2ubuntu0.5 | Not reported | Not reported | Not reported |
| Ubuntu | libssh | deb | 26.04 | 0.11.3-1ubuntu2.1 | Not reported | UBUNTU-CVE-2026-59849 | Not reported |
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [libssh-4]Not affected
Source package: [libssh]
Details (4)
0.10.6-0+deb12u2· amd64 · bookwormNot affected
nvd · libssh · debian · bookworm
0.10.6-0+deb12u2· arm64 · bookwormNot affected
nvd · libssh · debian · bookworm
0.10.6-0+deb12u1· amd64 · bookworm-securityNot affected
nvd · libssh · debian · bookworm
0.10.6-0+deb12u1· arm64 · bookworm-securityNot affected
nvd · libssh · debian · bookworm
- [libssh-dev]Not affected
Source package: [libssh]
Details (4)
0.10.6-0+deb12u2· amd64 · bookwormNot affected
nvd · libssh · debian · bookworm
0.10.6-0+deb12u2· arm64 · bookwormNot affected
nvd · libssh · debian · bookworm
0.10.6-0+deb12u1· amd64 · bookworm-securityNot affected
nvd · libssh · debian · bookworm
0.10.6-0+deb12u1· arm64 · bookworm-securityNot affected
nvd · libssh · debian · bookworm
- [libssh-doc]Not affected
Source package: [libssh]
Details (4)
0.10.6-0+deb12u2· all · bookwormNot affected
nvd · libssh · debian · bookworm
0.10.6-0+deb12u2· all · bookwormNot affected
nvd · libssh · debian · bookworm
0.10.6-0+deb12u1· all · bookworm-securityNot affected
nvd · libssh · debian · bookworm
0.10.6-0+deb12u1· all · bookworm-securityNot affected
nvd · libssh · debian · bookworm
- [libssh-gcrypt-4]Not affected
Source package: [libssh]
Details (4)
0.10.6-0+deb12u2· amd64 · bookwormNot affected
nvd · libssh · debian · bookworm
0.10.6-0+deb12u2· arm64 · bookwormNot affected
nvd · libssh · debian · bookworm
0.10.6-0+deb12u1· amd64 · bookworm-securityNot affected
nvd · libssh · debian · bookworm
0.10.6-0+deb12u1· arm64 · bookworm-securityNot affected
nvd · libssh · debian · bookworm
- [libssh-gcrypt-dev]Not affected
Source package: [libssh]
Details (4)
0.10.6-0+deb12u2· amd64 · bookwormNot affected
nvd · libssh · debian · bookworm
0.10.6-0+deb12u2· arm64 · bookwormNot affected
nvd · libssh · debian · bookworm
0.10.6-0+deb12u1· amd64 · bookworm-securityNot affected
nvd · libssh · debian · bookworm
0.10.6-0+deb12u1· arm64 · bookworm-securityNot affected
nvd · libssh · debian · bookworm
Observed:
References
- [https://ftp.suse.com/pub/projects/security/csaf/suse-su-2026_22940-1.json]
- [https://nvd.nist.gov/vuln/detail/CVE-2026-59849]
- [https://osv.dev/vulnerability/UBUNTU-CVE-2026-59849]
- [https://security-tracker.debian.org/tracker/CVE-2026-59849]
- [https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-59849.json]
- [https://ubuntu.com/security/notices/USN-8699-1]
- [https://wid.cert-bund.de/.well-known/csaf/white/2026/wid-sec-w-2026-2428.json]
[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX] · [Ubuntu Security Notices (USN)]