CVE-2026-39819

Invoking "go bug" follows symlinks in predictable temporary filenames in cmd/go

State: Published
Severity: 5.3 Medium
Published: May 7, 2026
Updated: May 8, 2026
Reserved: Apr 7, 2026

Description

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.

Scores

CVSS	Score	Vector	Source
3.1	5.3 Medium	CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:H/A:N	CISA-ADP

Weaknesses

The record names no weakness.

Affected Products

Product	Versions
cmd/goGo toolchain	before 1.25.10Affected 1.26.0-0 to before 1.26.3Affected

References

https://go.dev/issue/78584
https://go.dev/cl/763882
https://groups.google.com/g/golang-announce/c/qcCIEXso47M
https://pkg.go.dev/vuln/GO-2026-4978

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