CVE-2026-33811

Aliases:GO-2026-4981BIT-golang-2026-33811
Advisory lineage Upstream: 0 Downstream: 23
Analyzed
Published: 07 May 2026, 19:41
Last modified:21 Jul 2026, 12:05

Vulnerability Summary

Overall Risk (default)
medium
30/100
CVSS Score
7.5 HIGH
v3.1 (cve.org)
EPSS Score
0.81% LOW
1% probability 0.00%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

07 May 2026, 19:41
Published
Vulnerability first disclosed
21 Jul 2026, 12:05
Last Modified
Vulnerability information updated

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.

CVSS Metrics

  • v3.1•HIGH•Score: 7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Trends

Current EPSS score: 0.81%• Percentile: 53%

Techniques & Countermeasures

  • CWE-415•Double Free

    The product calls free() twice on the same memory address.

  • CWE-1341•Multiple Releases of Same Resource or Handle

    The product attempts to close or release a resource or handle more than once, without any successful open between the close operations.

Affected Systems

  • go standard library•net

    < 1.25.10 | ≥ 1.26.0-0, < 1.26.3

  • golang•go

    < 1.25.10 | ≥ 1.26.0, < 1.26.3

  • Go•stdlib

    ≥ 1.26.0-0, < 1.26.3

References (57)