CVE-2026-3706: mkj Dropbear
Affects dropbearSource GCVE Database
Not known to be exploited · CVSS 6.3 Medium.
Data as of 27 Oct 2026, 06:42 UTC
CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:UExploitation evidence
Disclosed: evidence found.
CVE published 8 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10dropbearpkg:deb/ubuntu/dropbear?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSdropbearpkg:deb/ubuntu/dropbear?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 25.10dropbearpkg:deb/ubuntu/dropbear?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSdropbearpkg:deb/ubuntu/dropbear?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 22.04 LTSdropbearpkg:deb/ubuntu/dropbear?arch=source&distro=jammyOther threats | Affected
| Fixed in– |
Ubuntu Pro 20.04 LTSdropbearpkg:deb/ubuntu/dropbear?arch=source&distro=esm-apps/focalOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
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.
References
- ubuntu.com/security/CVE-2026-3706 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-3706 (opens in a new tab)
- github.com/mkj/dropbear/issues/406 (opens in a new tab)
- github.com/mkj/dropbear/pull/407 (opens in a new tab)
- github.com/mkj/dropbear/ (opens in a new tab)
- github.com/mkj/dropbear/commit/fdec3c90a15447bd538641d85e5a3e3ac981011d (opens in a new tab)
- github.com/mkj/dropbear/issues/406 (opens in a new tab)
- github.com/str4d/ed25519-java/issues/82 (opens in a new tab)
- vuldb.com (opens in a new tab)
- vuldb.com (opens in a new tab)
- vuldb.com (opens in a new tab)