7.5

CVE-2026-33811: Crash when handling long CNAME response in net

Modified
AliasesRHSA-2026:36617RHSA-2026:36776RHSA-2026:39266
Published 07-05-2026Last modified 18-09-2026

Vulnerability summary

CVE-2026-33811 is a high (CVSS 7.5) Double Free vulnerability in go standard library net. EPSS estimates a 0.88% chance of exploitation in the next 30 days, higher than 59% of scored vulnerabilities.

Priority
Prioritisesevere

Severe, CVSS 7.5 (CVE.org); no exploitation reported by the 5 checked sources; EPSS 1% (FIRST, 03-11-2026)

Source freshness unavailable

How is this decided?
CVSS score
7.5/10
010
High · v3.1 (CVE.org)
EPSS score
0.88%
0%100%
Low · +0.06 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 57 · Related 58

Timeline

  1. 07-05-2026
    PublishedVulnerability first disclosed.
  2. 18-09-2026
    Last modifiedVulnerability 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

8 scores · 8 sources · 1 version

EPSS trend

Probability

0.88%

Chance of exploitation in the next 30 days

Percentile

59%

Versus all other CVEs

30-day change

Increase +0.06 pp

From 0.81% 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: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Chainguard198 products
  • aactl< 0.4.12-r51 | < 0.4.12-r50
  • actAll versions (No fix recorded)
  • actions-runner-controller-fips< 0.14.1-r2 | < 0.14.1-r1 | All versions (No fix recorded)
  • addon-resizerAll versions (No fix recorded)
  • addon-resizer-fipsAll versions (No fix recorded)
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 3391

References

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