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Fencer Intel
low 2.5

CVE-2026-4541 json

janmojzis tinyssh Ed25519 Signature crypto_sign_ed25519_tinyssh.c signature verification

published 7mo ago modified 4mo ago also EUVD-2026-14291

cvss
2.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 0%
public exploits
0
none known

Summary

A flaw has been found in janmojzis tinyssh up to 20250501. Impacted is an unknown function of the file tinyssh/crypto_sign_ed25519_tinyssh.c of the component Ed25519 Signature Handler. This manipulation causes improper verification of cryptographic signature. The attack is restricted to local execution. The attack's complexity is rated as high. The exploitability is considered difficult. The exploit has been published and may be used. Upgrading to version 20260301 is recommended to address this issue. Patch name: 9c87269607e0d7d20174df742accc49c042cff17. Upgrading the affected component is recommended.

Patch / fix

  • janmojzis tinyssh 20260301
  • tinyssh Debian 14 20260301-1

debian advisories DEBIAN-CVE-2026-4541

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CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
7mo ago

Exploit prediction

0.09% chance of exploitation in the next 30 days, higher than 0% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • github.com https://github.com/janmojzis/tinyssh/issues/101#issue-3983586116 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 2.0 CVSS:4.0/AV:L/AC:H/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P
CNA 3.1 2.5 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N/E:P/RL:O/RC:C
CNA 3.0 2.5 CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N/E:P/RL:O/RC:C
CNA 2.0 1.0 AV:L/AC:H/Au:S/C:N/I:P/A:N/E:POC/RL:OF/RC:C
CNA 4.0 1.1 CVSS:4.0/AV:L/AC:H/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P/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
CNA 3.1 2.5 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N
CNA 2.0 1.0 AV:L/AC:H/Au:S/C:N/I:P/A:N

Affected products

  • janmojzis tinyssh

Classification

Weakness
  • CWE-347 Improper Verification of Cryptographic Signature
  • CWE-345 Insufficient Verification of Data Authenticity

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.