CVE-2026-4926
path-to-regexp vulnerable to Denial of Service via sequential optional groups
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.
No summary for this CVE yet.
CVSS Vector Breakdown
Exploitability
AV:NAttack VectorNetwork
AC:LAttack ComplexityLow
PR:NPrivileges RequiredNone
UI:NUser InteractionNone
Scope
S:UScopeUnchanged
Impact
C:NConfidentialityNone
I:NIntegrityNone
A:HAvailabilityHigh
Weaknesses
Affected Products
path-to-regexp
oss-project
pillarjs
oss-project
Exploitability
No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.
Attack Graph
Products CVE Techniques Tactics
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MITRE ATT&CK
1 technique Impact
References
https://cna.openjsf.org/security-advisories.html
cna.openjsf.org
https://access.redhat.com/errata/RHSA-2026:10153
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:10172
access.redhat.com
and 19 more references View all →
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