CVE-2026-39819: Go toolchain cmd/go · Insecure Temporary File
Affects Go toolchain cmd/goSource CVE Database V5
Not known to be exploited · CVSS 5.3 Medium : upgrade to 1.26.3 or 1.25.10 when convenient.
Data as of 30 Oct 2026, 20:25 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 7% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 1.26.3, 1.25.10
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:H/A:NExploitation evidence
Disclosed: evidence found.
CVE published 7 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.
What to do
Upgrade Go toolchain cmd/go to 1.26.3 or 1.25.10.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Go toolchaincmd/go | Affected
| Fixed in
|
| Go toolchaincmd/go | Affected
| Fixed in
|
Gocmd/gopkg:golang/cmd/goOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Users should exercise caution when running the 'go bug' command in environments where untrusted users have access to the system temporary directory.
Description
CVE-2026-39819 is a medium severity vulnerability in the Go toolchain's cmd/go component. The 'go bug' command creates temporary files with predictable names in the system temporary directory. This allows an attacker with access to that directory to create symbolic links with those names, potentially causing the command to overwrite unintended files.