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High 7.5Published Jun 2, 2026
CVE-2026-42504Quadratic complexity in WordDecoder.DecodeHeader in mime
Updated under an hour ago ()
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It affects Go standard library mime. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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Decoding a maliciously-crafted MIME header containing many invalid encoded-words can consume excessive CPU.
- CVSS
- 7.5 HIGH (v3.1, CISA ADP)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Weakness (CWE)
- CWE-407
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Go
- NVD analysis
- Awaiting Analysis
- Record last updated
- Oct 19, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Go standard library mime go_standard_library:mime (from the name) | before 1.25.11; from 1.26.0-0 before 1.26.4 | CNA record |
References
- https://go.dev/issue/79217
- https://go.dev/cl/774481
- https://groups.google.com/g/golang-announce/c/tKs3rmcBcKw
- https://pkg.go.dev/vuln/GO-2026-5038
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.