GHSA-56wx-66px-9j66
OPKSSH Vulnerable to Authentication Bypass
Packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| Go | github.com/openpubkey/opkssh | < 0.5.0 | 0.5.0 |
Details
As written in the advisory (Markdown source, shown as plain text).
### 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:
```bash
opkssh --version
```
If the version is less than 0.5.0 you should upgrade. To upgrade to the latest version run:
```bash
wget -qO- "https://raw.githubusercontent.com/openpubkey/opkssh/main/scripts/install-linux.sh" | sudo bash
```
### References
[CVE-2025-4658](https://www.cve.org/CVERecord?id=CVE-2025-4658)
The upstream vulnerability in OpenPubkey is [CVE-2025-3757](https://www.cve.org/CVERecord?id=CVE-2025-3757) and has the security advisory https://github.com/openpubkey/openpubkey/security/advisories/GHSA-537f-gxgm-3jjq
References
External links from the advisory. They lead to third-party sites.