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VulnerabilityPublished Updated

CVE-2026-39819: The "go bug" command writes to two files with predictable names in the system temporary directory

Source GCVE Database

0
Authoritative record:CVE-2026-39819· Medium 5.3

Not known to be exploited · CVSS 5.3 Medium : upgrade to 1.26.3 or 1.25.10 when convenient.

Data as of 27 Oct 2026, 00:07 UTC

CVSS 3.1 base score
5.3Medium
How severe the flaw is on the 0–10 CVSS scale.
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:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 7 May 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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 26 Oct 2026.

What to do

Upgrade cmd/go to 1.26.3 or 1.25.10.

Affected software

ProductAffectedFixed in
Go toolchaincmd/goAffected
  • >=1.26.0-0 <1.26.3
Fixed in
  • 1.26.3
Go toolchaincmd/goAffected
  • <1.25.10
Fixed in
  • 1.25.10
Gocmd/gopkg:golang/cmd/goOther threatsAffected
  • <1.25.10
  • >=1.26.0-0 <1.26.3
Fixed in
  • 1.25.10
  • 1.26.3

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

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.

References

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