CVE-2026-59846

LOW 3.9

Published 2026-07-21 · Last modified 2026-08-19

A flaw was found in libssh. A malicious username expanded through %r in ProxyCommand handling can inject shell metacharacters, exposing environment variables and causing unintended shell behavior.

NO EXPLOITATION SIGNALS

No known exploitation, public exploit, or elevated probability at this time. Track for changes.

Exploitation likelihood

0.1%chance of exploitation in 30 days · 2nd percentile

○ In CISA KEV ○ Public exploit / PoC

Impact if exploited

3.9CVSS 3.1 · LOW

ConfidentialityLow
IntegrityLow
AvailabilityNone

What an attacker needs

⚠Access: Requires local access to the host
⚠Privileges: Requires a low-privilege account
⚠User interaction: A user must take an action (click / open a file)
✓Complexity: No special conditions — reliably repeatable

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept & exploit code

github-search Search GitHub for public PoC repos

Test against your own equipment

curl -s https://vulnpedia.com/cve/CVE-2026-59846/poc.jsonMachine-readable PoC index for this CVE (for automation).

Listed for defensive triage, patch verification, and authorized testing on systems you own. Machine-readable: /cve/CVE-2026-59846/poc.json

Affected

Vendors Red Hat Libssh Redhat

Products Red Hat Enterprise Linux 10 Red Hat Hardened Images Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 9 Libssh Hardened Images Enterprise Linux

Weakness (CWE)

CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
CWE-77: Improper Neutralization of Special Elements used in a Command ('Command Injection')

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N

Known Affected Software Configurations

Vendor	Product	Version range
Libssh	Libssh	*
Redhat	Hardened Images	*
Redhat	Enterprise Linux	8.0
Redhat	Enterprise Linux	9.0
Redhat	Enterprise Linux	10.0

All CVSS metrics

LOW 3.9 v3.1 · CNA Primary
CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N
LOW 3.9 v3.1 · NVD Secondary
CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N

References

Advisories

https://access.redhat.com/errata/RHSA-2026:42922 vendor-advisoryx_refsource_REDHATVendor Advisory
https://access.redhat.com/errata/RHSA-2026:55855 vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/security/cve/CVE-2026-59846 vdb-entryx_refsource_REDHATVendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2498179 issue-trackingx_refsource_REDHATIssue TrackingVendor Advisory

Sources: NVD · CVE.org · EPSS