CVE-2026-3706

CVE-2026-3706 · mkj Dropbear S Range Check curve25519.c unpackneg signature verification

This page contains facts from public vulnerability sources. Check the original advisory before updating.

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 6.3 · Medium · EPSS 0.2% · Fix available

Published

2026-03-08T05:02:11.136Z

Updated

2026-04-22T18:54:11.224Z

Stack: system

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