5.3

CVE-2026-39819: Invoking "go bug" follows symlinks in predictable temporary filenames in cmd/go

Analyzed
AliasesUBUNTU-CVE-2026-39819DEBIAN-CVE-2026-39819CGA-2242-9rhf-jrw5
Published 07-05-2026Last modified 08-05-2026

Vulnerability summary

CVE-2026-39819 is a medium (CVSS 5.3) vulnerability in go toolchain cmd/go. EPSS estimates a 0.18% chance of exploitation in the next 30 days, higher than 7.5% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 5.3, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
5.3/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.18%
0%100%
Low · +0.03 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 16 · Related 17

Timeline

  1. 07-05-2026
    PublishedVulnerability first disclosed.
  2. 08-05-2026
    Last modifiedVulnerability information updated.

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 metrics

7 scores · 7 sources · 1 version

EPSS trend

Probability

0.18%

Chance of exploitation in the next 30 days

Percentile

8%

Versus all other CVEs

30-day change

Increase +0.03 pp

From 0.15% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Chainguard198 products
  • aactl< 0.4.12-r50 | < 0.4.12-r51
  • act< 0.2.88-r2
  • actions-runner-controller-fips< 0.14.1-r2 | < 0.14.1-r1
  • addon-resizer< 1.8.23-r19 | < 1.8.23-r18
  • addon-resizer-fips< 1.8.23-r18
Alpine2 products
  • go≥ 1.26.0, < 1.25.10-r0 | ≥ 1.26.0, < 1.26.3-r0
  • rclone< 1.74.1-r0

2 vendors · 200 products · Showing 200 of 3395

References

13 links
Show all 13 references