CVE-2026-39817

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

MEDIUM
5.9
CVSS Score
Published: May 7, 2026 at 07:41 PM UTC
Updated: June 17, 2026 at 10:42 AM UTC
2 products affected across 2 vendorsGoGo

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Severity
MEDIUM5.9
Exploit prediction
EPSS 0.2%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 1.25.101.26.0 ≤ v < 1.26.3
v < 1.25.101.26.0-0 ≤ v < 1.26.31.26.0-0
Affected range stops below 1.25.10, so it looks safe — our inference, not a vendor statement
Affected range stops below 1.26.3, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (4)

Issue Tracking
Source: cverecord
https://go.dev/issue/78778
Patch
Source: cverecord
https://go.dev/cl/767520
Issue TrackingMailing List
Source: cverecord
https://groups.google.com/g/golang-announce/c/qcCIEXso47M
Vendor Advisory
Source: cverecord
https://pkg.go.dev/vuln/GO-2026-4979

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.9MEDIUMCISA-ADP
Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality
NONE
Integrity
HIGH
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-787

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