Medium severity · published May 7, 2026
CVE-2026-39817
Invoking "go tool pack" does not sanitize output paths in cmd/go
5.9
CVSS
0.2%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:N/I:H/A:N
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
Required
Confidentiality
None
Integrity
High
Availability
None
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 6% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
CM
cmd/go · Go toolchain
before 1.25.10; 1.26.0-0 before 1.26.3 · source: vendor
GO
GO · Golang
before 1.25.10; 1.26.0 before 1.26.3 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-39817
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-39817
Patch
https://go.dev/cl/767520
Issue Tracking
https://go.dev/issue/78778
Issue Tracking
https://groups.google.com/g/golang-announce/c/qcCIEXso47M
Vendor Advisory
https://pkg.go.dev/vuln/GO-2026-4979
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