CVE-2026-39817

Invoking "go tool pack" does not sanitize output paths in cmd/go

CVSS 5.9 MEDIUMEPSS 0.2%

Vexday Risk Score

13Low

SSVC decision (CISA)

Track

No exploitation signal → monitor

CVSS 5.9EPSS 0.2%KEV nãoPoC —Nuclei —Metasploit —Patch —

Lifecycle

07 May 2026Published on NVD

Recommendation: Monitor — no exploitation signal at the moment.

The "go tool pack" subcommand (usually used only by the compiler as an internal tool with known-good inputs) does not sanitize output filenames. Extracting a malicious archive file with the "pack" subcommand can write files to arbitrary locations on the filesystem.

CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:N/I:H/A:N

Affected products

Go toolchain · cmd/go

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References

https://go.dev/cl/767520 https://go.dev/issue/78778 https://groups.google.com/g/golang-announce/c/qcCIEXso47M https://pkg.go.dev/vuln/GO-2026-4979