Medium severity · published Sep 29, 2026
CVE-2026-102824
Russh: Missing X25519 zero-point validation in hybrid ML-KEM key exchange
4.3
CVSS
0.1%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
Low
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.1% · higher than 3% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
RU
russh · Eugeny
< 0.63.0 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-102824
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-102824
x_refsource_CONFIRM
https://github.com/Eugeny/russh/security/advisories/GHSA-w3jg-pjxf-73p4
x_refsource_MISC
https://github.com/Eugeny/russh/commit/8da8967f196472576b1565d518a0ed60fce60f0c
x_refsource_MISC
https://github.com/Eugeny/russh/releases/tag/v0.63.0
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