Invoking "go tool pack" does not sanitize output paths in cmd/go (CVE-2026-39817) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-39817

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

Answer in brief

CVE-2026-39817 records a Unknown severity vulnerability in Invoking "go tool pack" does not sanitize output paths in cmd/go. The current sources do not mark it as known exploited. The current feed maps toolchain (go). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published May 7, 2026Updated Aug 26, 2026Source checked Aug 26, 2026First seen by HOL Aug 26, 2026Material review Aug 26, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps toolchain (go). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
toolchaingo	>=0 <1.25.10 >=1.26.0-0 <1.26.3	1.25.10, 1.26.3

Recommended response

Check inventory. Check lockfiles and deployed manifests for toolchain.
Review the reported fix. Update toolchain to 1.25.10 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
May 7, 2026
Evidence: source:osv:source_dates:source-dates:record
Source modified
Aug 26, 2026
Evidence: source:osv:source_dates:source-dates:record
First seen by HOL
Aug 26, 2026

Sources and claim methodology

Upstream source description

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.

Quoted source text, attributed separately from HOL analysis.