What is CVE-2026-39833?

CVE-2026-39833 is a critical-severity vulnerability in Golang Crypto, classified under Missing Authorization. CVSS score: 9.1/10. Published 2026-05-22.

How severe is CVE-2026-39833?

Critical severity. CVSS v3 base score is 9.1 out of 10.

Auth bypass in Golang Crypto

CVE-2026-39833

The in-memory keyring returned by NewKeyring() silently accepted keys with the ConfirmBeforeUse constraint but never enforced it. The key would sign without any confirmation prompt, with no indication to the caller that the constraint was not in effect. NewKeyring() now returns an error when unsupported constraints are requested.

Vulnerability class: Broken Access Control

Published 2026-05-22 · last modified 2026-08-11.

CVSS v3 metric

CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.

EPSS exploit prediction

EPSS: 0.005 (40.6th percentile), scored 2026-10-19.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 41st percentile — 40.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.004 · newest: 0.005 · change: +0.001

Affected products

Golang Crypto
Golang.org/x/crypto Golang.org/x/crypto/ssh/agent — versions 0

Weakness classification (CWE)

CWE-862 — Missing Authorization

References

go.dev/issue/79436 (Issue Tracking)
go.dev/cl/778640 (Issue Tracking)
go.dev/cl/778641 (Issue Tracking)
groups.google.com/g/golang-announce/c/a082jnz-LvI (Mailing List)
pkg.go.dev/vuln/GO-2026-5005 (Vendor Advisory)
go.dev/cl/778642

Frequently asked questions

What is CVE-2026-39833?: CVE-2026-39833 is a critical-severity vulnerability in Golang Crypto, classified under Missing Authorization. CVSS score: 9.1/10. Published 2026-05-22.
How severe is CVE-2026-39833?: Critical severity. CVSS v3 base score is 9.1 out of 10.