CVE-2026-39820: Quadratic string concatentation in consumeComment in net/mail

Published May 7, 2026
·
Updated

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

Affected Software

3 affected components
golang/net/mail
Golang Go<1.25.10
Golang Go>=1.26.0<1.26.3

Remediation

Event History

May 7, 2026
CVE Published
via MITRE·07:41 PM
Data Sourced
via MITRE·07:41 PM
DescriptionWeakness
Data Sourced
via NVD·08:16 PM
RemedyDescriptionSeverityWeaknessAffected Software
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Frequently Asked Questions

1

What is the severity of CVE-2026-39820?

CVE-2026-39820 is classified as a moderate severity vulnerability due to its potential for CPU exhaustion and memory allocation issues.

2

How do I fix CVE-2026-39820?

To fix CVE-2026-39820, update the golang/net/mail package to the latest version where the vulnerability has been addressed.

3

What impact does CVE-2026-39820 have on system performance?

CVE-2026-39820 can lead to significant performance degradation, causing excessive CPU usage and memory allocation during specific input handling.

4

Which versions of golang/net/mail are affected by CVE-2026-39820?

CVE-2026-39820 affects older versions of the golang/net/mail package prior to the vulnerability fix in later updates.

5

Can CVE-2026-39820 be exploited remotely?

Yes, CVE-2026-39820 can potentially be exploited remotely if an attacker sends specially crafted inputs to the affected functions.

Contact

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