Skip to content
Fencer Intel
medium 4.3

CVE-2026-102824 json

Russh: Missing X25519 zero-point validation in hybrid ML-KEM key exchange

published last mo. modified last mo. also EUVD-2026-89207 , GHSA-w3jg-pjxf-73p4

cvss
4.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 3%
public exploits
0
none known

Summary

Russh is a Rust SSH client and server library. Prior to 0.63.0, the hybrid ML-KEM 768 and X25519 implementation in russh/src/kex/hybrid_mlkem.rs accepts an all-zero 32-byte peer X25519 public key in both server_dh and compute_shared_secret, forcing the X25519 contribution to the combined shared secret to zero. A malicious SSH peer can therefore make the combined secret depend only on ML-KEM, defeating the hybrid exchange's intended fallback protection if ML-KEM is later weakened. This issue is fixed in version 0.63.0.

Patch / fix

  • crates.io russh 0.63.0
  • warpgate_project warpgate 0.63.0
  • russh_project russh 0.63.0
  • rust-russh Debian 14 0.64.1-1

debian advisories DEBIAN-CVE-2026-102824

  • openshell hummingbird 1 0.1.2-0.2.hum1
  • openshell-gateway hummingbird 1 0.1.2-0.2.hum1
  • python3-openshell hummingbird 1 0.1.2-0.2.hum1

red hat advisories RHSA-2026:74586

Is CVE-2026-102824 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-102824 updated cvss 4.3

russh: russh: Cryptographic fallback bypass via missing public key validation

  • Red Hat Hardened Images openshell 0.1.2-0.2.hum1, openshell-gateway 0.1.2-0.2.hum1, python3-openshell 0.1.2-0.2.hum1
    fixed: vendor fix RHSA-2026:74586

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
last mo.

Exploit prediction

0.14% chance of exploitation in the next 30 days, higher than 3% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
GitHub 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

Affected packages

ecosystem package affected fixed in
crates.io russh
<0.63.0
0.63.0

Affected products

  • Eugeny russh

Classification

Weakness
  • CWE-327 Use of a Broken or Risky Cryptographic Algorithm

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.