CVE-2026-42504

Quadratic complexity in WordDecoder.DecodeHeader in mime

High · published June 2, 2026

CVSS v3.1
7.5
EPSS
1%
Percentile
45.9
In the wild
Unconfirmed
What it is

Decoding a maliciously-crafted MIME header containing many invalid encoded-words can consume excessive CPU.

The record
Technical detail
CVSS v3.1
7.5 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS v4.0
Not supplied
EPSS
0.00560 · 45.9th percentile
Published
2026-06-02T22:01Z
EPSS history
Timeline
  • 02 JUN 22:01Z
    Quadratic complexity in WordDecoder.DecodeHeader in mime
    cvelistv5