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No exploitation reportedFix available

CVE-2026-59842

No exploitation reported by the sources we read.

  • Published2026-07-21
  • WeaknessCWE-125

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

A flaw was found in libssh. During server-side GSSAPI key exchange, a client-supplied Curve25519 public key shorter than the expected length is copied without proper length validation, leading to an out-of-bounds heap read. This could allow a remote unauthenticated attacker to disclose small amounts of server memory.

Timeline

dates in UTC
  1. 2026-07-2112:18CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-11-03 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-59842?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-59842?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Libssh
BranchAffectedFixed in
0.12= 0.12.0no fix published
Redhat enterprise linux
BranchAffectedFixed in
10.0= 10.0no fix published
10.2= 10.2no fix published
Redhat enterprise linux for ibm z systems
BranchAffectedFixed in
10.0= 10.0no fix published
10.2= 10.2no fix published

8 more products in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Products declared by the CNA4 products

As redhat, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2026-08-19

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • libsshWolfiall versions · fixed in 0.12.1-r0and 1 other package
  • libsshRocky Linux:10all versions · fixed in 0:0.12.0-3.el10_2
  • libsshRed Hat:hummingbird:1all versions · fixed in 0:0.12.1-4.hum1and 2 other packages
  • libsshRed Hat:enterprise_linux:10.2all versions · fixed in 0:0.12.0-3.el10_2and 4 other packages
  • libsshMinimOSall versions · fixed in 0.12.1-r0and 1 other package
  • libsshDebian:14all versions · fixed in 0.12.1-1
  • libsshChainguardall versions · fixed in 0.12.1-r0and 1 other package
  • libsshAlpine:v3.24all versions · fixed in 0.12.1-r0

4 more package ranges on OSV.dev

Vendor advisories

  • CVE-2026-59842 Red Hat Product Security30 products fixed

    libssh: libssh: information disclosure via short GSSAPI Curve25519 public key

  • RHSA-2026:55855 Red Hat Product Security26 products fixed

    Red Hat Security Advisory: libssh security update

  • RHSA-2026:42922 Red Hat Product Security7 products fixed

    Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update

Full record on NVD

Fix

  1. Vendor fix Red Hat Product Security RHSA-2026:55855 · 26 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
  2. Vendor fix Red Hat Product Security RHSA-2026:42922 · 7 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://images.redhat.com/
  3. Workaround from the vendor Red Hat Product Security RHSA-2026:55855 · 26 productsDisable GSSAPIKeyExchange or remove gss-curve25519-sha256- from GSSAPIKexAlgorithms if appropriate.

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub
Metasploit modules
none listed
Metasploit Framework

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Published
2026-07-21
Last Modified
2026-09-22
NVD status
Analyzed
GitHub Advisory
GHSA-x94w-cg8g-g593

Frequently asked questions

What is CVE-2026-59842?

A flaw was found in libssh. During server-side GSSAPI key exchange, a client-supplied Curve25519 public key shorter than the expected length is copied without proper length validation, leading to an out-of-bounds heap read. This could allow a remote unauthenticated attacker to disclose small amounts of server memory.

Is CVE-2026-59842 actively exploited?

Active exploitation of CVE-2026-59842 has not been confirmed. Its EPSS score was 0.5% on 2026-11-03, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-59842?

CVE-2026-59842 has a CVSS v3 base score of 5.3 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N.

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Sources for this record