CVE-2026-39820

Description

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

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: 0.05%• Percentile: 17%

Techniques & Countermeasures

• CWE-770•Allocation of Resources Without Limits or Throttling

  The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.

Affected Systems

• go standard library•net/mail

  < 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 (4)

• https://go.dev/issue/78566
• https://go.dev/cl/759940
• https://groups.google.com/g/golang-announce/c/qcCIEXso47M
• https://pkg.go.dev/vuln/GO-2026-4986