Vulnerability · Published Jul 21, 2026 · Assigned by redhat
CVE-2026-59848Libssh: libssh: denial of service via sftp responses with unknown request ids
Medium 5.3
In plain English
A medium-severity resource allocation without limits in Red Hat Enterprise Linux 10 from Red Hat. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 28% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)5.3Medium
Exploit odds (30 days)0.3%top 72.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
A flaw was found in libssh. A malicious SFTP server can send responses for unknown request IDs that libssh clients keep queued indefinitely, causing unbounded memory growth and client-side denial of service.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:10 | libssh | 0.12.0-3.el10_2 | ALSA-2026:55855 |
| AlmaLinux:8 | libssh | 0.9.6-17.el8_10 | ALSA-2026:62218 |
| AlmaLinux:9 | libssh | 0.10.4-19.el9_8 | ALSA-2026:62217 |
| AlmaLinux:10 | libssh-config | 0.12.0-3.el10_2 | ALSA-2026:55855 |
| AlmaLinux:8 | libssh-config | 0.9.6-17.el8_10 | ALSA-2026:62218 |
| AlmaLinux:9 | libssh-config | 0.10.4-19.el9_8 | ALSA-2026:62217 |
| AlmaLinux:10 | libssh-devel | 0.12.0-3.el10_2 | ALSA-2026:55855 |
| AlmaLinux:8 | libssh-devel | 0.9.6-17.el8_10 | ALSA-2026:62218 |
| AlmaLinux:9 | libssh-devel | 0.10.4-19.el9_8 | ALSA-2026:62217 |
| Alpine:v3.24 | libssh | 0.12.1-r0 | ALPINE-CVE-2026-59848 |
| Debian:12 | libssh | 0.10.6-0+deb12u3 | DEBIAN-CVE-2026-59848 |
| Debian:13 | libssh | 0.11.5-0+deb13u1 | DEBIAN-CVE-2026-59848 |
| Debian:14 | libssh | 0.12.1-1 | DEBIAN-CVE-2026-59848 |
| Rocky Linux:10 | libssh | 0:0.12.0-3.el10_2 | RLSA-2026:55855 |
| Rocky Linux:8 | libssh | 0:0.9.6-17.el8_10 | RLSA-2026:62218 |
| Rocky Linux:9 | libssh | 0:0.10.4-19.el9_8 | RLSA-2026:62217 |
| Ubuntu:22.04:LTS | libssh | 0.9.6-2ubuntu0.22.04.8 | UBUNTU-CVE-2026-59848 |
| Ubuntu:22.04:LTS | libssh | 0.9.6-2ubuntu0.22.04.8 | USN-8699-1 |
| Ubuntu:24.04:LTS | libssh | 0.10.6-2ubuntu0.5 | UBUNTU-CVE-2026-59848 |
| Ubuntu:24.04:LTS | libssh | 0.10.6-2ubuntu0.5 | USN-8699-1 |
| Ubuntu:26.04:LTS | libssh | 0.11.3-1ubuntu2.1 | USN-8699-1 |
| Ubuntu:26.04:LTS | libssh | 0.11.3-1ubuntu2.1 | UBUNTU-CVE-2026-59848 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Red Hat | Red Hat Enterprise Linux 10 | see references |
| Red Hat | Red Hat Enterprise Linux 8 | see references |
| Red Hat | Red Hat Enterprise Linux 8 | see references |
| Red Hat | Red Hat Enterprise Linux 9 | see references |
| Red Hat | Red Hat Enterprise Linux 9 | see references |
| Red Hat | Red Hat Hardened Images | see references |
Weakness: CWE-770 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
References
- RHSA-2026:42922 vendor-advisory, x_refsource_REDHAT
- RHSA-2026:55855 vendor-advisory, x_refsource_REDHAT
- RHSA-2026:62217 vendor-advisory, x_refsource_REDHAT
- RHSA-2026:62218 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/security/cve/CVE-2026-59848 vdb-entry, x_refsource_REDHAT
- RHBZ#2498181 issue-tracking, x_refsource_REDHAT