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

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.

Published: 2026-05-07 Last update: 2026-05-13 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-39817 is rated Low Risk (26.1/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.17%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-39817

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.03% 0.17% +0.14%
2 2026-05-08 — 0.03% —

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-39817

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.9 3.1 MEDIUM
CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:N/I:H/A:N Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 1.5 4.0 [email protected]
5.9 3.1 MEDIUM
CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:N/I:H/A:N Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 1.5 4.0 134c704f-9b21-4f2e-91b3-4a467353bcc0

Weakness enumeration for CVE-2026-39817

GitHub Security Advisory for CVE-2026-39817

GHSA-qc64-m6c2-v4x7 · Severity: medium — The "go tool pack" subcommand (usually used only by the compiler as an internal tool with known...

OS Trackers for CVE-2026-39817

vendor priority summary link
debian not yet assigned CVE-2026-39817 not yet assigned priority: Debian including 5 source packages (golang-1.15, golang-1.19, golang-1.24, golang-1.25, golang-1.26), 7 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 4, open 3. https://security-tracker.debian.org/tracker/CVE-2026-39817
suse medium CVE-2026-39817 severity moderate: SUSE including 13 source package names (go, go-doc, …), 105 product×package rows across 17 product lines (SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS, SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS, … (17 product lines)): First Fixed 72, Known Not Affected 29, Fixed 4. https://www.suse.com/security/cve/CVE-2026-39817/
ubuntu medium CVE-2026-39817 medium priority: Ubuntu including 16 source packages (golang, golang-1.10, …), 98 status rows across 9 suites (bionic, focal, jammy, noble, questing, resolute, trusty, upstream, xenial): needs-triage 52, DNE 46. https://ubuntu.com/security/CVE-2026-39817

Affected software / configurations for CVE-2026-39817

Vendor Product Version Raw CPE
golang go < 1.25.10 cpe:2.3:a:golang:go:*:*:*:*:*:*:*:*
golang go >= 1.26.0, < 1.26.3 cpe:2.3:a:golang:go:*:*:*:*:*:*:*:*

References for CVE-2026-39817

cvelogic Threat Intelligence