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Fencer Vulns
critical 9.8

CVE-2025-4658 json

Authentication Bypass in OPKSSH

published 2025-05-13 17 mo ago modified 2026-06-17 4 mo ago also GHSA-56wx-66px-9j66 , GO-2025-3680 , EUVD-2025-14477

cvss
9.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 27%
public exploits
0
none known

Summary

Versions of OpenPubkey library prior to 0.10.0 contained a vulnerability that would allow a specially crafted JWS to bypass signature verification. As OPKSSH depends on the OpenPubkey library for authentication, this vulnerability in OpenPubkey also applies to OPKSSH versions prior to 0.5.0 and would allow an attacker to bypass OPKSSH authentication.

Patch / fix

  • go github.com/openpubkey/opkssh 0.5.0
  • openpubkey openpubkey 0.10.0
  • openpubkey opkssh 0.5.0
  • govulncheck-vulndb openSUSE Tumbleweed 0.0.20250515T200012-1.1

opensuse advisories openSUSE-SU-2025:15135-1

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
total
Assessed
17 mo ago

Exploit prediction

0.34% chance of exploitation in the next 30 days, higher than 27% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 9.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L
CNA 4.0 9.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L/E:X/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
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
go github.com/openpubkey/opkssh
<0.5.0
0.5.0

Affected products

  • OPKSSH OPKSSH

Classification

Weakness
  • CWE-305 Authentication Bypass by Primary Weakness
  • CWE-347 Improper Verification of Cryptographic Signature

References

Sources

Fencer Vulns 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.