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CVE.org (no NVD analysis yet)· CNA GitHub_M

CVE-2026-102824: Russh: Missing X25519 zero-point validation in hybrid ML-KEM key exchange

MediumCVSS 4.3 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 17/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.14% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Eugeny russh 0.63.0.

Low priority for now. Upgrade to Eugeny russh 0.63.0 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

Published
Sep 29, 2026
Updated
Sep 30, 2026
EPSS
0.1% · 3th percentile

Report tools

JSON

Action score

17

Monitor

Low priority for now.

CVSS
17 / 40 · 4.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · GitHub_M
4.3
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

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Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • Eugeny russh

    • < 0.63.0affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
crates.iorusshbefore 0.63.00.63.0
Debian:14rust-russhbefore 0.64.1-10.64.1-1
Red Hat:hummingbird:1openshellbefore 0:0.1.2-0.2.hum10:0.1.2-0.2.hum1
Red Hat:hummingbird:1openshell-gatewaybefore 0:0.1.2-0.2.hum10:0.1.2-0.2.hum1
Red Hat:hummingbird:1python3-openshellbefore 0:0.1.2-0.2.hum10:0.1.2-0.2.hum1

Same product

eugeny: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-116794russh: Agent server never calls `Agent::confirm`, so keys added with the confirm constraint (`ssh-add -c`) sign without confirmation
    33Monitor
  • CVE-2026-102823russh: Client-side channel-scoped Handler callbacks fire for channel IDs the client never opened
    30Monitor
  • CVE-2026-48110Russh: SSH message fields were decoded through allocation-first parsers before field-specific bounds
    30Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-102821Sep 29, 2026 · Russh: Unbounded memory exhaustion via CHANNEL_OPEN flood during a client-stalled rekey
    26Monitor
  • ← EarlierCVE-2026-102822Sep 29, 2026 · russh: negotiating a MAC-requiring block cipher (CTR/CBC) with mac=none causes a slice-index-out-of-range panic
    14Monitor
  • Later →CVE-2026-102825Sep 29, 2026 · Russh: Configured server auth-attempt cap is not enforced in the USERAUTH_REQUEST runtime path
    14Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Eugeny russh0.63.0 · descriptionVendor (CNA)
crates.io:russh0.63.0Package registry (OSV)
debian:rust-russh0.64.1-1 · Debian:14Package registry (OSV)
red hat:openshell0:0.1.2-0.2.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:openshell-gateway0:0.1.2-0.2.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:python3-openshell0:0.1.2-0.2.hum1 · Red Hat:hummingbird:1Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. Fix recordedsame day
  3. TodayNov 14, 2026+45 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Not on record for this CVE: researcher credit · variant or chain candidate · public bounty program.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
low · data can be read
Integrity
none
Availability
none
Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
Low
Integrity impact
None
Availability impact
None

Weakness class (CWE)

CWE-327 · Use of a Broken or Risky Cryptographic Algorithm

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Change log

  1. SSVC exploitation— → none
  2. Exploit maturity— → none
  3. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

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