CVE-2026-3706

  1. OpenCVE
  2. Vulnerabilities (CVE)
  3. CVE-2026-3706
A vulnerability was determined in mkj Dropbear up to 2025.89. Impacted is the function unpackneg of the file src/curve25519.c of the component S Range Check. This manipulation causes improper verification of cryptographic signature. The attack can be initiated remotely. The attack is considered to have high complexity. The exploitability is considered difficult. The actual existence of this vulnerability is currently in question. Patch name: fdec3c90a15447bd538641d85e5a3e3ac981011d. To fix this issue, it is recommended to deploy a patch. The project maintainer explains: "Signature Malleability is not exploitable in SSH protocol. (...) [A] PoC doesn't exist for SSH implementation, but rather it's against the internal API."

3.7 /10

CVSS v3 : LOW

V3 Legend

Vector :

Exploitability : 2.2 / Impact : 1.4

Attack Vector NETWORK

Attack Complexity HIGH

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact LOW

Availability Impact NONE

Scope UNCHANGED

2.6 /10

CVSS v2.0 : LOW

V2 Legend

Vector : AV:N/AC:H/Au:N/C:N/I:P/A:N

Exploitability : 4.9 / Impact : 2.9

Access Vector NETWORK

Access Complexity HIGH

Authentication NONE

Confidentiality Impact NONE

Integrity Impact PARTIAL

Availability Impact NONE

References
Link Resource
https://github.com/mkj/dropbear/
https://github.com/mkj/dropbear/commit/fdec3c90a15447bd538641d85e5a3e3ac981011d
https://github.com/mkj/dropbear/issues/406
https://github.com/mkj/dropbear/pull/407
https://github.com/str4d/ed25519-java/issues/82#issue-727629226
https://vuldb.com/?ctiid.349652
https://vuldb.com/?id.349652
https://vuldb.com/?submit.765933
https://github.com/mkj/dropbear/issues/406
Configurations

No configuration.

History

22 Apr 2026, 20:16

Type Values Removed Values Added
References () https://github.com/mkj/dropbear/issues/406 - () https://github.com/mkj/dropbear/issues/406 -

16 Mar 2026, 14:19

Type Values Removed Values Added
References
  • {'url': 'https://github.com/mkj/dropbear/issues/406#issue-3978907798', 'source': 'cna@vuldb.com'}
  • () https://github.com/mkj/dropbear/issues/406 -
Summary
  • (es) Se determinó una vulnerabilidad en mkj Dropbear hasta 2025.89. La función unpackneg del archivo src/curve25519.c del componente S Range Check se ve afectada. Esta manipulación provoca una verificación incorrecta de la firma criptográfica. El ataque puede iniciarse de forma remota. Se considera que el ataque tiene una complejidad alta. La explotabilidad se considera difícil. El exploit ha sido divulgado públicamente y puede ser utilizado. Nombre del parche: fdec3c90a15447bd538641d85e5a3e3ac981011d. Para solucionar este problema, se recomienda desplegar un parche.
Summary (en) A vulnerability was determined in mkj Dropbear up to 2025.89. Impacted is the function unpackneg of the file src/curve25519.c of the component S Range Check. This manipulation causes improper verification of cryptographic signature. The attack can be initiated remotely. The attack is considered to have high complexity. The exploitability is considered difficult. The exploit has been publicly disclosed and may be utilized. Patch name: fdec3c90a15447bd538641d85e5a3e3ac981011d. To fix this issue, it is recommended to deploy a patch. (en) A vulnerability was determined in mkj Dropbear up to 2025.89. Impacted is the function unpackneg of the file src/curve25519.c of the component S Range Check. This manipulation causes improper verification of cryptographic signature. The attack can be initiated remotely. The attack is considered to have high complexity. The exploitability is considered difficult. The actual existence of this vulnerability is currently in question. Patch name: fdec3c90a15447bd538641d85e5a3e3ac981011d. To fix this issue, it is recommended to deploy a patch. The project maintainer explains: "Signature Malleability is not exploitable in SSH protocol. (...) [A] PoC doesn't exist for SSH implementation, but rather it's against the internal API."

08 Mar 2026, 05:16

Type Values Removed Values Added
New CVE
Information

Published : 2026-03-08 05:16

Updated : 2026-04-22 21:27

NVD link : CVE-2026-3706

Mitre link : CVE-2026-3706

CVE.ORG link : CVE-2026-3706

JSON object : View

Products Affected

No product.

CWE
CWE-345

Insufficient Verification of Data Authenticity

CWE-347

Improper Verification of Cryptographic Signature