mkj Dropbear S Range Check curve25519.c unpackneg signature verification
Summary
| CVE | CVE-2026-3706 |
|---|---|
| State | PUBLISHED |
| Assigner | VulDB |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-03-08 05:16:31 UTC |
| Updated | 2026-04-22 21:27:27 UTC |
| 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 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." |
Risk And Classification
Primary CVSS: v4.0 1.7 LOW from [email protected]
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:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Problem Types: CWE-345 | CWE-347 | CWE-347 Improper Verification of Cryptographic Signature | CWE-345 Insufficient Verification of Data Authenticity
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | [email protected] | Secondary | 1.7 | LOW | 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:U/C... |
| 4.0 | CNA | DECLARED | 6.3 | MEDIUM | 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:U |
| 3.1 | [email protected] | Secondary | 3.7 | LOW | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N |
| 3.1 | CNA | DECLARED | 3.7 | LOW | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N/E:U/RL:O/RC:C |
| 3.0 | CNA | DECLARED | 3.7 | LOW | CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N/E:U/RL:O/RC:C |
| 2.0 | [email protected] | Secondary | 2.6 | AV:N/AC:H/Au:N/C:N/I:P/A:N | |
| 2.0 | CNA | DECLARED | 2.6 | AV:N/AC:H/Au:N/C:N/I:P/A:N/E:U/RL:OF/RC:C |
CVSS v4.0 Breakdown
Attack Vector
NetworkAttack Complexity
HighAttack Requirements
NonePrivileges Required
NoneUser Interaction
NoneConfidentiality
NoneIntegrity
LowAvailability
NoneSub Conf.
NoneSub Integrity
NoneSub Availability
NoneCVSS: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:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
HighPrivileges Required
NoneUser Interaction
NoneScope
UnchangedConfidentiality
NoneIntegrity
LowAvailability
NoneCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
CVSS v3.0 Breakdown
Attack Vector
NetworkAttack Complexity
HighPrivileges Required
NoneUser Interaction
NoneScope
UnchangedConfidentiality
NoneIntegrity
LowAvailability
NoneCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N/E:U/RL:O/RC:C
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Mkj | Dropbear | affected 2025.0 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.1 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.2 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.3 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.4 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.5 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.6 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.7 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.8 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.9 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.10 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.11 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.12 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.13 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.14 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.15 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.16 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.17 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.18 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.19 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.20 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.21 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.22 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.23 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.24 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.25 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.26 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.27 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.28 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.29 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.30 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.31 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.32 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.33 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.34 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.35 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.36 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.37 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.38 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.39 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.40 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.41 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.42 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.43 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.44 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.45 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.46 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.47 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.48 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.49 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.50 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.51 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.52 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.53 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.54 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.55 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.56 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.57 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.58 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.59 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.60 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.61 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.62 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.63 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.64 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.65 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.66 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.67 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.68 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.69 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.70 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.71 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.72 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.73 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.74 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.75 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.76 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.77 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.78 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.79 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.80 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.81 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.82 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.83 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.84 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.85 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.86 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.87 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.88 | Not specified |
| CNA | Mkj | Dropbear | affected 2025.89 | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| vuldb.com | [email protected] | vuldb.com | |
| vuldb.com | [email protected] | vuldb.com | |
| github.com/mkj/dropbear/commit/fdec3c90a15447bd538641d85e5a3e3ac981011d | [email protected] | github.com | |
| github.com/mkj/dropbear/issues/406 | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | github.com | |
| github.com/mkj/dropbear | [email protected] | github.com | |
| github.com/str4d/ed25519-java/issues/82 | [email protected] | github.com | |
| vuldb.com | [email protected] | vuldb.com | |
| github.com/mkj/dropbear/pull/407 | [email protected] | github.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: pythok (VulDB User) (en)
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| CNA | 2026-03-07T00:00:00.000Z | Advisory disclosed |
| CNA | 2026-03-07T01:00:00.000Z | VulDB entry created |
| CNA | 2026-03-16T06:42:50.000Z | VulDB entry last update |
There are currently no legacy QID mappings associated with this CVE.