What is CVE-2026-39820?

CVE-2026-39820 is a high-severity vulnerability in Golang Go, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 7.5/10. Published 2026-05-07.

How severe is CVE-2026-39820?

High severity. CVSS v3 base score is 7.5 out of 10.

Resource exhaustion in Golang Go

CVE-2026-39820

Well-crafted inputs reaching ParseAddress, ParseAddressList, and ParseDate were able to trigger excessive CPU exhaustion and memory allocations.

EPSS: 0.001 (17.1th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Golang Go
Go Standard Library Net/mail — versions 0, 1.26.0-0

Weakness classification (CWE)

CWE-770 — Allocation of Resources Without Limits or Throttling

References

security@golang.org (Issue Tracking)
security@golang.org (Patch)
security@golang.org (Mailing List, Issue Tracking)
security@golang.org (Vendor Advisory)

Frequently asked questions

What is CVE-2026-39820?: CVE-2026-39820 is a high-severity vulnerability in Golang Go, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 7.5/10. Published 2026-05-07.
How severe is CVE-2026-39820?: High severity. CVSS v3 base score is 7.5 out of 10.