Skip to main content
VulnerabilityPublished Updated

CVE-2026-33811: Go standard library net · Double Free

Affects Go standard library netSource CVE Database V5

0
Compare

Not known to be exploited · CVSS 7.5 High : upgrade to 1.26.3 or 1.25.10 soon.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 3.1 base score
7.5High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.8% chance of exploitation in 30 days – higher than 58% 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:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 7 May 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: 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 30 Oct 2026.

What to do

Upgrade Go standard library net to 1.26.3 or 1.25.10.

Affected software

ProductAffectedFixed in
Go standard librarynetAffected
  • >=1.26.0-0 <1.26.3
Fixed in
  • 1.26.3
Go standard librarynetAffected
  • <1.25.10
Fixed in
  • 1.25.10
Gonetpkg:golang/netOther threatsAffected
  • =0
  • =1.26.0-0
Fixed in–
Gonetpkg:golang/netOther 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.

AI-suggested

A fix is available via configuration change: applications should be configured to use the pure Go DNS resolver instead of the cgo DNS resolver by setting the environment variable GODEBUG=netdns=go. This mitigation requires restarting affected applications or services. Users should verify that this change does not negatively affect DNS resolution in their environment.

Description

When using LookupCNAME with the cgo DNS resolver, a very long CNAME response can trigger a double-free of C memory and a crash.

References

Community reviews

Loading reviews…