CVE-2026-39832

When adding a key to a remote agent constraint extensions such as restrict-destination-v00@openssh.com were not serialized in the request. Destination restrictions were silently stripped when forwarding keys, allowing unrestricted use of the key on the remote host. The client now serializes all constraint extensions. Additionally, the in-memory keyring returned by NewKeyring() now rejects keys with unsupported constraint extensions instead of silently ignoring them.

What this means for your business

It affects Golang Crypto. It matters if your company, or a supplier that handles your data, runs it.
An attacker can use it remotely, over a network, without a login, and without anyone at your company clicking anything.
FIRST's prediction model gives it a 0.6% chance of attack attempts being seen in the next 30 days, ranking above 46% of all known flaws.

What to do

1Check whether your company or your suppliers run Golang Crypto, and which version. The affected versions are listed further down this page.
2If you do, apply the vendor's fix. A patch or vendor advisory has been published.

Not sure if your company is exposed?

Fastnexa’s certified penetration testers can check whether attackers could use this flaw, or others like it, against your websites, apps and network. The full test is free for our first 10 founding clients until 31 December 2026.

Check if you’re exposed Book a call

Scoring

CVSS: 9.1 (v3.1)
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Weakness: CWE-502
Assigned by: security@golang.org

Dates

Published: 2026-05-22
Last modified: 2026-09-15
Sources: NVD

Affected products

Golang Crypto- 0.52.0

As listed in the NVD configuration data. Not a statement about your estate.