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6.5
CVE-2026-59844: Libssh SFTP Denial of Service via Oversized Read Request
CVE-2026-59844 · published 3 months ago
Summary
A vulnerability in libssh's SFTP server can cause it to run out of memory when handling large read requests from a remote client. This could potentially allow an attacker to disrupt the SFTP service. To mitigate this issue, update to the latest version of libssh.
What to do
- Update bellsoft libssh to version 0.12.1-r0.
Affected software
| Ecosystem | Vendor | Product | Affected versions |
|---|---|---|---|
| Debian:12 | debian | libssh | All versions |
| Debian:13 | debian | libssh | All versions |
| Debian:14 | debian | libssh | All versions |
| Ubuntu:26.04:LTS | canonical | libssh | All versions |
| – | red hat | red hat enterprise linux 10 | All versions |
| – | red hat | red hat enterprise linux 8 | All versions |
| – | red hat | red hat enterprise linux 9 | All versions |
| – | red hat | red hat hardened images | All versions |
| Debian:11 | debian | libssh | All versions |
| Alpaquita:stream | bellsoft | libssh |
>= 0.9.6-r1, < 0.12.1-r0 Fix: upgrade to 0.12.1-r0
|
| – | libssh | libssh |
All versions
cpe:2.3:a:libssh:libssh:-:*:*:*:*:*:*:* |
| – | redhat | hardened_images |
All versions
cpe:2.3:a:redhat:hardened_images:-:*:*:*:*:*:*:* |
| – | redhat | enterprise_linux |
8.0 9.0 10.0 cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:* |
Original advisory text
Libssh: libssh: denial of service via oversized sftp read length
A flaw was found in libssh. A remote authenticated client can issue SSH_FXP_READ requests with an arbitrarily large length, causing a libssh SFTP server to allocate excessive memory and potentially exhaust it through repeated requests.
References
- https://security-tracker.debian.org/tracker/CVE-2026-59844 Vendor Advisory
- https://docs.bell-sw.com/security/cves/CVE-2026-59844 Vendor Advisory
- https://access.redhat.com/errata/RHSA-2026:42922 Vendor Advisory
- https://access.redhat.com/security/cve/CVE-2026-59844 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2498177 Issue Tracking Vendor Advisory
- https://access.redhat.com/errata/RHSA-2026:55855
- https://access.redhat.com/errata/RHSA-2026:62218
- https://www.cve.org/CVERecord?id=CVE-2026-59844 Third Party Advisory
- https://ubuntu.com/security/CVE-2026-59844 Third Party Advisory
- https://www.libssh.org/security/advisories/CVE-2026-59844.txt Third Party Advisory
- https://www.libssh.org/2026/07/21/libssh-0-12-1-and-0-11-5-security-releases/ Third Party Advisory
- https://access.redhat.com/errata/RHSA-2026:62217
Internet-facing
60 days
Internal
At next upgrade
- Not known to be exploited
- Needs hands-on effort to exploit
- Gives an attacker partial control
Type
CWE-789Memory Allocation with Excessive Size Value
Timeline
Published21 Jul 2026
Updated4 Nov 2026
First seen21 Jul 2026
Sources
CVE-2026-59844 · NVD
CVE-2026-59844 · MITRE
DEBIAN-CVE-2026-59844 · OSV
BELL-CVE-2026-59844 · OSV
UBUNTU-CVE-2026-59844 · OSV
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