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."

CVSS v3 3.7 LOW
CVSS v2.0 2.6 LOW

3.7^/10

CVSS v3 : LOW

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

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

Configurations

No configuration.

History

No history.

Information

Published : 2026-03-08 05:16

Updated : 2026-03-16 14:19

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

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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.\""}, {"lang": "es", "value": "Se determin\u00f3 una vulnerabilidad en mkj Dropbear hasta 2025.89. La funci\u00f3n unpackneg del archivo src/curve25519.c del componente S Range Check se ve afectada. Esta manipulaci\u00f3n provoca una verificaci\u00f3n incorrecta de la firma criptogr\u00e1fica. El ataque puede iniciarse de forma remota. Se considera que el ataque tiene una complejidad alta. La explotabilidad se considera dif\u00edcil. El exploit ha sido divulgado p\u00fablicamente y puede ser utilizado. Nombre del parche: fdec3c90a15447bd538641d85e5a3e3ac981011d. Para solucionar este problema, se recomienda desplegar un parche."}], "lastModified": "2026-03-16T14:19:52.480", "sourceIdentifier": "cna@vuldb.com"}