What is CVE-2026-39819?

CVE-2026-39819 is a medium-severity vulnerability in Golang Go, classified under Improper Link Resolution Before File Access. CVSS score: 5.3/10. Published 2026-05-07.

How severe is CVE-2026-39819?

Medium severity. CVSS v3 base score is 5.3 out of 10.

Vulnerability in Golang Go

CVE-2026-39819

The "go bug" command writes to two files with predictable names in the system temporary directory (for example, "/tmp"). An attacker with access to the temporary directory can create a symlink in one of these names, causing "go bug" to overwrite the target of the symlink.

Published 2026-05-07 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:H/A:N.

EPSS exploit prediction

EPSS: 0.001 (3.4th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 3rd percentile — 3.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.002 · newest: 0.001 · change: -0.000

Affected products

Golang Go
Go Toolchain Cmd/go — versions 0, 1.26.0-0

Weakness classification (CWE)

CWE-59 — Improper Link Resolution Before File Access

References

go.dev/issue/78584 (Issue Tracking)
go.dev/cl/763882 (Patch)
groups.google.com/g/golang-announce/c/qcCIEXso47M (Mailing List, Issue Tracking)
pkg.go.dev/vuln/GO-2026-4978 (Vendor Advisory)

Frequently asked questions

What is CVE-2026-39819?: CVE-2026-39819 is a medium-severity vulnerability in Golang Go, classified under Improper Link Resolution Before File Access. CVSS score: 5.3/10. Published 2026-05-07.
How severe is CVE-2026-39819?: Medium severity. CVSS v3 base score is 5.3 out of 10.