CVE-2026-4926
Medium
Elevated severity or exploit probability.
CVSS base
7.5
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS — probability of exploitation (30 days)
0.9%
57.7th percentile
CISA KEV
Not listed
Weakness / dates
CWE-1333
Published 2026-03-26 · modified 2026-09-09
Description
Impact: A bad regular expression is generated any time you have multiple sequential optional groups (curly brace syntax), such as `{a}{b}{c}:z`. The generated regex grows exponentially with the number of groups, causing denial of service. Patches: Fixed in version 8.4.0. Workarounds: Limit the number of sequential optional groups in route patterns. Avoid passing user-controlled input as route patterns.
Affected
References
- https://cna.openjsf.org/security-advisories.html
- https://access.redhat.com/errata/RHSA-2026:10153
- https://access.redhat.com/errata/RHSA-2026:10172
- https://access.redhat.com/errata/RHSA-2026:10175
- https://access.redhat.com/errata/RHSA-2026:13545
- https://access.redhat.com/errata/RHSA-2026:13826
- https://access.redhat.com/errata/RHSA-2026:17789
- https://access.redhat.com/errata/RHSA-2026:19409
- https://access.redhat.com/errata/RHSA-2026:19410
- https://access.redhat.com/errata/RHSA-2026:24761
- https://access.redhat.com/errata/RHSA-2026:24762
- https://access.redhat.com/errata/RHSA-2026:24866
- https://access.redhat.com/errata/RHSA-2026:36651
- https://access.redhat.com/errata/RHSA-2026:40118
- https://access.redhat.com/errata/RHSA-2026:40945
- https://access.redhat.com/errata/RHSA-2026:50300
- https://access.redhat.com/errata/RHSA-2026:65126
- https://access.redhat.com/errata/RHSA-2026:9385
- https://access.redhat.com/errata/RHSA-2026:9742
- https://access.redhat.com/security/cve/CVE-2026-4926
- https://bugzilla.redhat.com/show_bug.cgi?id=2451867
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4926.json