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Fencer Vulns
high 8.8

CVE-2026-42503 json

Accidental binding to INADDR_ANY might lead to RCE in golang.org/x/tools/gopls

published 2026-05-06 6 mo ago modified 2026-10-26 13 d ago also EUVD-2026-27872

cvss
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 11%
public exploits
0
none known

Summary

gopls by default communicates via pipe. However, -port and -listen flags are supported as means of debugging. If -listen is given a value without an explicit host (e.g. :8080), or -port is used, gopls will listen on 0.0.0.0.  As a result, users might inadvertently cause gopls to bind 0.0.0.0. This can allow a malicious party on the same network to execute code arbitrarily via gopls.

Patch / fix

  • golang.org/x/tools golang.org/x/tools/gopls 0.22.0
  • gopls Debian 14 2:0.22.0+ds-1

debian advisories DEBIAN-CVE-2026-42503

  • golang1.25 hummingbird 1 1.25.9-1.hum1
  • golang1.25-bin hummingbird 1 1.25.9-1.hum1
  • golang1.25-src hummingbird 1 1.25.9-1.hum1
  • golang1.25-misc hummingbird 1 1.25.9-1.hum1
  • golang1.25-tests hummingbird 1 1.25.9-1.hum1
  • golang1.25-shared hummingbird 1 1.25.9-1.hum1
  • golang1.26 hummingbird 1 1.26.2-1.1.hum1
  • golang1.26-bin hummingbird 1 1.26.2-1.1.hum1

red hat advisories RHSA-2026:7385RHSA-2026:8291

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-42503 updated cvss 8.8

golang: golang.org/x/tools/gopls: gopls: Arbitrary code execution due to insecure network binding

  • Red Hat Hardened Images golang1.25 1.25.9-1.hum1, golang1.26 1.26.2-1.1.hum1
    fixed: vendor fix RHSA-2026:7385
  • Red Hat Hardened Images trivy 0.69.3-1.1.hum1
    not affected: vulnerable code not in execute path

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
6 mo ago

Exploit prediction

0.21% chance of exploitation in the next 30 days, higher than 11% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 8.8 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA 3.1 8.8 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

  • golang.org/x/tools golang.org/x/tools/gopls

Classification

Weakness
  • CWE-1327 Binding to an Unrestricted IP Address

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.