CPU Exhaustion and Memory Allocation Vulnerability in Go Programming Language
CVE-2026-39820

Currently unrated

Key Information:

Vendor: Go Standard Library
Status: Net/mail
Vendor: CVE Published:; 7 May 2026

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What is CVE-2026-39820?

A vulnerability exists in the Go programming language that allows specially crafted inputs to functions such as ParseAddress, ParseAddressList, and ParseDate, leading to excessive CPU exhaustion and unwanted memory allocations. This can severely affect the performance of applications utilizing these functions, potentially causing a denial of service as systems become overwhelmed with resource demands.

Affected Version(s)

net/mail 0 < 1.25.10

net/mail 1.26.0-0 < 1.26.3

References

https://go.dev/issue/78566

https://go.dev/cl/759940

https://groups.google.com/g/golang-announce/c/qcCIEXso47M

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Timeline

Vulnerability published
May 7, 2026
Vulnerability Reserved
Apr 7, 2026

Credit

thatnealpatel

CVE-2026-39820 Data

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