CVE-2026-39820

Quadratic string concatentation in consumeComment in net/mail

Published May 7, 2026 CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed
Description
Well-crafted inputs reaching ParseAddress, ParseAddressList, and ParseDate were able to trigger excessive CPU exhaustion and memory allocations.

Remediation

No solution or workaround provided in the CVE record

Tracking

Sign in to view the affected projects.

Advisories

No advisories available
References
Link Providers
https://access.redhat.com/errata/RHSA-2026:22112 cve-icon
https://access.redhat.com/errata/RHSA-2026:22120 cve-icon
https://access.redhat.com/errata/RHSA-2026:22121 cve-icon
https://access.redhat.com/errata/RHSA-2026:23262 cve-icon
https://access.redhat.com/errata/RHSA-2026:23264 cve-icon
https://access.redhat.com/errata/RHSA-2026:33120 cve-icon
https://access.redhat.com/errata/RHSA-2026:33123 cve-icon
https://access.redhat.com/errata/RHSA-2026:33142 cve-icon
https://access.redhat.com/errata/RHSA-2026:33150 cve-icon
https://access.redhat.com/errata/RHSA-2026:33574 cve-icon
https://access.redhat.com/errata/RHSA-2026:34364 cve-icon
https://access.redhat.com/errata/RHSA-2026:36319 cve-icon
https://access.redhat.com/errata/RHSA-2026:36625 cve-icon
https://access.redhat.com/errata/RHSA-2026:36754 cve-icon
https://access.redhat.com/errata/RHSA-2026:36797 cve-icon
https://access.redhat.com/errata/RHSA-2026:40262 cve-icon
https://access.redhat.com/errata/RHSA-2026:41031 cve-icon
https://access.redhat.com/errata/RHSA-2026:41066 cve-icon
https://access.redhat.com/errata/RHSA-2026:41928 cve-icon
https://access.redhat.com/errata/RHSA-2026:42146 cve-icon
https://access.redhat.com/errata/RHSA-2026:42644 cve-icon
https://access.redhat.com/errata/RHSA-2026:42796 cve-icon
https://access.redhat.com/errata/RHSA-2026:43038 cve-icon
https://access.redhat.com/errata/RHSA-2026:43052 cve-icon
https://access.redhat.com/errata/RHSA-2026:43692 cve-icon
https://access.redhat.com/errata/RHSA-2026:47952 cve-icon
https://access.redhat.com/errata/RHSA-2026:49702 cve-icon
https://access.redhat.com/errata/RHSA-2026:49712 cve-icon
https://access.redhat.com/errata/RHSA-2026:50205 cve-icon
https://access.redhat.com/errata/RHSA-2026:50300 cve-icon
https://access.redhat.com/errata/RHSA-2026:50319 cve-icon
https://access.redhat.com/errata/RHSA-2026:50336 cve-icon
https://access.redhat.com/errata/RHSA-2026:50843 cve-icon
https://access.redhat.com/errata/RHSA-2026:51033 cve-icon
https://access.redhat.com/errata/RHSA-2026:51112 cve-icon
https://access.redhat.com/errata/RHSA-2026:54274 cve-icon
https://access.redhat.com/errata/RHSA-2026:54283 cve-icon
https://access.redhat.com/errata/RHSA-2026:54284 cve-icon
https://access.redhat.com/errata/RHSA-2026:54285 cve-icon
https://access.redhat.com/errata/RHSA-2026:54286 cve-icon
https://access.redhat.com/errata/RHSA-2026:54287 cve-icon
https://access.redhat.com/errata/RHSA-2026:54531 cve-icon
https://access.redhat.com/errata/RHSA-2026:54552 cve-icon
https://access.redhat.com/errata/RHSA-2026:54555 cve-icon
https://access.redhat.com/errata/RHSA-2026:54583 cve-icon
https://access.redhat.com/errata/RHSA-2026:54602 cve-icon
https://access.redhat.com/errata/RHSA-2026:54883 cve-icon
https://access.redhat.com/errata/RHSA-2026:56340 cve-icon
https://access.redhat.com/errata/RHSA-2026:56789 cve-icon
https://access.redhat.com/errata/RHSA-2026:56852 cve-icon
https://access.redhat.com/errata/RHSA-2026:56854 cve-icon
https://access.redhat.com/errata/RHSA-2026:57194 cve-icon
https://access.redhat.com/errata/RHSA-2026:57401 cve-icon
https://access.redhat.com/errata/RHSA-2026:57482 cve-icon
https://access.redhat.com/errata/RHSA-2026:57487 cve-icon
https://access.redhat.com/errata/RHSA-2026:57649 cve-icon
https://access.redhat.com/errata/RHSA-2026:57845 cve-icon
https://access.redhat.com/errata/RHSA-2026:57914 cve-icon
https://access.redhat.com/errata/RHSA-2026:59467 cve-icon
https://access.redhat.com/errata/RHSA-2026:59830 cve-icon
https://access.redhat.com/errata/RHSA-2026:59833 cve-icon
https://access.redhat.com/errata/RHSA-2026:60018 cve-icon
https://access.redhat.com/errata/RHSA-2026:60023 cve-icon
https://access.redhat.com/errata/RHSA-2026:60520 cve-icon
https://access.redhat.com/errata/RHSA-2026:61253 cve-icon
https://access.redhat.com/errata/RHSA-2026:62260 cve-icon
https://access.redhat.com/errata/RHSA-2026:62406 cve-icon
https://access.redhat.com/errata/RHSA-2026:62407 cve-icon
https://access.redhat.com/errata/RHSA-2026:62753 cve-icon
https://access.redhat.com/errata/RHSA-2026:62754 cve-icon
https://access.redhat.com/errata/RHSA-2026:62803 cve-icon
https://access.redhat.com/errata/RHSA-2026:63022 cve-icon
https://access.redhat.com/errata/RHSA-2026:65116 cve-icon
https://access.redhat.com/errata/RHSA-2026:65117 cve-icon
https://access.redhat.com/errata/RHSA-2026:65153 cve-icon
https://access.redhat.com/errata/RHSA-2026:65335 cve-icon
https://access.redhat.com/errata/RHSA-2026:65336 cve-icon
https://access.redhat.com/errata/RHSA-2026:65534 cve-icon
https://access.redhat.com/errata/RHSA-2026:65838 cve-icon
https://access.redhat.com/errata/RHSA-2026:65886 cve-icon
https://access.redhat.com/errata/RHSA-2026:65895 cve-icon
https://access.redhat.com/errata/RHSA-2026:66016 cve-icon
https://access.redhat.com/errata/RHSA-2026:66022 cve-icon
https://access.redhat.com/errata/RHSA-2026:66327 cve-icon
https://access.redhat.com/errata/RHSA-2026:67517 cve-icon
https://access.redhat.com/errata/RHSA-2026:67974 cve-icon
https://access.redhat.com/errata/RHSA-2026:67975 cve-icon
https://access.redhat.com/errata/RHSA-2026:68334 cve-icon
https://access.redhat.com/errata/RHSA-2026:68504 cve-icon
https://access.redhat.com/errata/RHSA-2026:68527 cve-icon
https://access.redhat.com/security/cve/CVE-2026-39820 cve-icon
https://bugzilla.redhat.com/show_bug.cgi?id=2467820 cve-icon
https://go.dev/cl/759940 cve-icon cve-icon
https://go.dev/issue/78566 cve-icon cve-icon
https://groups.google.com/g/golang-announce/c/qcCIEXso47M cve-icon cve-icon
https://pkg.go.dev/vuln/GO-2026-4986 cve-icon cve-icon
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-39820.json cve-icon
History
Type Values Removed Values Added
First Time appeared Golang
Golang go
Weaknesses CWE-770
CPEs cpe:2.3:a:golang:go:*:*:*:*:*:*:*:*
Vendors & Products Golang
Golang go
Type Values Removed Values Added
Weaknesses CWE-739
Type Values Removed Values Added
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Go Standard Library
Go Standard Library net/mail
Weaknesses CWE-739
Vendors & Products Go Standard Library
Go Standard Library net/mail
Type Values Removed Values Added
Description Well-crafted inputs reaching ParseAddress, ParseAddressList, and ParseDate were able to trigger excessive CPU exhaustion and memory allocations.
Title Quadratic string concatentation in consumeComment in net/mail
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
Go
Published
Updated
Sep 18, 2026, 12:04 PM
Reserved
Apr 7, 2026, 6:13 PM
Status
Modified
Published
May 7, 2026, 8:16 PM
Modified
Oct 26, 2026, 12:10 AM