CVE-2026-42499
CVE-2026-42499 is a high-severity vulnerability in Golang Go with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-1046.
Key facts
- Severity: High (CVSS 3.x base score 7.5)
- EPSS exploit prediction: 1% (52nd percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-28432
- Weakness: CWE-1046
- Affected product: Golang Go
- Published:
- Last modified:
Description
Pathological inputs could cause DoS through consumePhrase when parsing an email address according to RFC 5322.
Frequently asked questions
- What is CVE-2026-42499?
- Pathological inputs could cause DoS through consumePhrase when parsing an email address according to RFC 5322.
- How severe is CVE-2026-42499?
- CVE-2026-42499 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
- Is CVE-2026-42499 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (52nd percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2026-42499?
- CVE-2026-42499 affects Golang Go. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2026-42499?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- Does CVE-2026-42499 have an EU (EUVD) identifier?
- Yes. CVE-2026-42499 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-28432.
- When was CVE-2026-42499 published?
- CVE-2026-42499 was published on 2026-05-07 and last updated on 2026-07-08.
References
- https://go.dev/cl/771520
- https://go.dev/issue/78987
- https://groups.google.com/g/golang-announce/c/qcCIEXso47M
- https://pkg.go.dev/vuln/GO-2026-4977
- https://access.redhat.com/errata/RHSA-2026:33120
- https://access.redhat.com/errata/RHSA-2026:33123
- https://access.redhat.com/errata/RHSA-2026:33142
- https://access.redhat.com/errata/RHSA-2026:33150
- https://access.redhat.com/errata/RHSA-2026:33574
- https://access.redhat.com/errata/RHSA-2026:34364
- https://access.redhat.com/errata/RHSA-2026:36319
- https://access.redhat.com/errata/RHSA-2026:36625
- https://access.redhat.com/security/cve/CVE-2026-42499
- https://bugzilla.redhat.com/show_bug.cgi?id=2467809
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42499.json
Affected products (1)
- cpe:2.3:a:golang:go:*:*:*:*:*:*:*:*
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