Medium severity · published May 7, 2026
CVE-2026-39819
Invoking "go bug" follows symlinks in predictable temporary filenames in cmd/go
5.3
CVSS
0.2%
EPSS
No
On KEV
Description
The "go bug" command writes to two files with predictable names in the system temporary directory (for example, "/tmp"). An attacker with access to the temporary directory can create a symlink in one of these names, causing "go bug" to overwrite the target of the symlink.
CVSS vector
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:H/A:N
Attack vector
Local
Complexity
High
Privileges
Low
User interaction
None
Confidentiality
Low
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 7% 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-2026-39819
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-39819
Patch
https://go.dev/cl/763882
Issue Tracking
https://go.dev/issue/78584
Issue Tracking
https://groups.google.com/g/golang-announce/c/qcCIEXso47M
Vendor Advisory
https://pkg.go.dev/vuln/GO-2026-4978
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