Eugeny Russh up to 0.62.3 Key Exchange curve25519.rs Curve25519Kex::server_dh input validation

CVSS Meta Temp Score
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CTI Interest Score
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5.1$0-$5k0.49

Summaryinfo

A vulnerability classified as problematic has been found in Eugeny Russh up to 0.62.3. This issue affects the function Curve25519Kex::server_dh of the file russh/src/kex/curve25519.rs of the component Key Exchange. Performing a manipulation results in input validation. This vulnerability was named CVE-2026-73430. The attack may be initiated remotely. There is no available exploit.

Detailsinfo

A vulnerability was found in Eugeny Russh up to 0.62.3. It has been classified as problematic. This affects the function Curve25519Kex::server_dh of the file russh/src/kex/curve25519.rs of the component Key Exchange. The manipulation with an unknown input leads to a input validation vulnerability. CWE is classifying the issue as CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. This is going to have an impact on availability. The summary by CVE is:

Russh is a Rust SSH client & server library. Prior to 0.62.4, an unauthenticated SSH client can cause a denial of service by sending SSH_MSG_KEX_ECDH_INIT with a 32-byte all-zero Q_C value. Curve25519Kex::server_dh in russh/src/kex/curve25519.rs accepts the all-zero peer public value and computes an all-zero shared secret, after which compute_exchange_hash calls encode_mpint in russh/src/kex/mod.rs and indexes beyond the end of the input while skipping leading zero bytes. The resulting panic occurs before authentication and terminates the server key-exchange task. This issue is fixed in version 0.62.4.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-73430 since 08/12/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 0.62.4 eliminates this vulnerability.

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Vendor

Name

Version

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.3
VulDB Meta Temp Score: 5.1

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Input validation
CWE: CWE-20
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Russh 0.62.4

Timelineinfo

08/12/2026 Advisory disclosed
08/12/2026 +0 days CVE reserved
08/12/2026 +0 days VulDB entry created
08/12/2026 +0 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-73430 (🔒)
GCVE (CVE): GCVE-0-2026-73430
GCVE (VulDB): GCVE-100-389283

Entryinfo

Created: 08/12/2026 23:25
Changes: 08/12/2026 23:25 (57)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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