8.8

CVE-2026-59851: libssh Incorrect Authorization

CVSS: 8.8v3.1HighModified
AliasesUBUNTU-CVE-2026-59851DEBIAN-CVE-2026-59851CGA-5p4m-2rwr-9m4g
Published 21-07-2026Last modified 17-08-2026
Open JSON

Vulnerability summary

CVE-2026-59851 is a high (CVSS 8.8) Incorrect Authorization vulnerability in libssh. EPSS estimates a 0.49% chance of exploitation in the next 30 days, higher than 40.7% of scored vulnerabilities.

Overall risk
35/100
0100
Medium · default modelHow is this calculated?
CVSS score
8.8/10
010
High · v3.1 (CVE.org)
EPSS score
0.49%
0%100%
Low · +0.20 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 2 · Related 1
RHSA-2026:42922RHSA-2026:55855CGA-W936-QQPJ-75GX

Timeline

  1. 21-07-2026
    PublishedVulnerability first disclosed.
  2. 17-08-2026
    Last modifiedVulnerability information updated.

Description

A flaw was found in libssh. On servers with GSSAPIKeyExchange enabled, the gssapi-keyex path does not verify whether the authenticated Kerberos principal is authorized for the requested local user, allowing authenticated clients to log in as arbitrary users.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.49%

Chance of exploitation in the next 30 days

Percentile

41%

Versus all other CVEs

30-day change

+0.20 pp

From 0.29% on 18-09-2026

18-09-202618-10-2026
EPSS score
0.49%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Chainguard3 products
  • libssh< 0.12.1-r0
  • libssh-dev< 0.12.1-r0
  • libssh2All versions (No fix recorded)
Wolfi3 products
  • libssh< 0.12.1-r0
  • libssh-dev< 0.12.1-r0
  • libssh2All versions (No fix recorded)
Redhat2 products
Debian1 product
  • libssh< 0.12.1-1
Libssh1 product
Ubuntu1 product
  • libsshAll versions (No fix recorded)

6 vendors · 11 products

References

9 links