How severe is CVE-2025-4658?

No CVSS score has been assigned to CVE-2025-4658 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2025-4658?

CVE-2025-4658 affects the following packages: github.com/openpubkey/opkssh (Go). Ecosystems affected: Go.

How do I fix CVE-2025-4658?

Update github.com/openpubkey/opkssh to 0.5.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-4658 is resolved across your whole dependency graph.

How do I detect CVE-2025-4658 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/openpubkey/opkssh, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2025-4658 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2025-4658 actively exploited in the wild?

No public exploit code has been indexed for CVE-2025-4658 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2025-4658?

CVE-2025-4658 has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 28th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2025-4658?

CVE-2025-4658 is classified as CWE-305 (CWE-305), CWE-347 (CWE-347). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2025-4658 published, and has it been updated?

CVE-2025-4658 was published on May 13, 2025 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹 Go

Not in CISA KEV

CVE-2025-4658 — opkssh

CVE-2025-4658 is a CWE-305 vulnerability in github.com/openpubkey/opkssh. A fix is available for github.com/openpubkey/opkssh — see the affected versions and patch details below.

Authentication Bypass in OPKSSH

Also known asGHSA-56wx-66px-9j66GO-2025-3680

Published

May 13, 2025

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 3, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
A successful exploit gives an attacker total control of the affected component, not partial access.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2025-4658.

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs28th percentile — riskier than 28% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

🐹github.com/openpubkey/opkssh

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

Impact

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.

Patches

The vulnerability does not exist in more recent versions of OPKSSH. his only impacts OPKSSH when used to verify ssh keys on a server, the OPKSSH client is unaffected. To remediate upgrade to a version of OPKSSH v0.5.0 or greater.

To determine if you are vulnerable run on your server:

opkssh --version

If the version is less than 0.5.0 you should upgrade. To upgrade to the latest version run:

wget -qO- "https://raw.githubusercontent.com/openpubkey/opkssh/main/scripts/install-linux.sh" | sudo bash

References

CVE-2025-4658

The upstream vulnerability in OpenPubkey is CVE-2025-3757 and has the security advisory https://github.com/openpubkey/openpubkey/security/advisories/GHSA-537f-gxgm-3jjq

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/openpubkey/opkssh`	all versions	0.5.0`go get github.com/openpubkey/opkssh@v0.5.0`

Affected Products

2 products · 2 configurations

Application

openpubkeyopenpubkey

< 0.10.0

range

Application

opksshopenpubkey

< 0.5.0

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/openpubkey/opkssh, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/openpubkey/opkssh to 0.5.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-4658 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

### Impact 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. ### Patches The vulnerability does not exist in more recent versions of OPKSSH. his only impacts OPKSSH when used to verify ssh keys on a server, the OPKSSH client is unaffected. To remediate upgrade to a version of OPKSSH v0.5.0 or

O3 Security · Impact-Aware SCA

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