CVE-2026-77423 JLine - Denial of Service

JLine 3.0.0 to 3.30.15 and 4.3.1 contain a denial of service caused by user-controlled nested-quantifier regex patterns in the built-in less viewer, letting attackers cause excessive CPU usage and session blocking, exploit requires sending crafted patterns.

CVSS base score 7.5 /10
High
CISA KEV
Not listed
Public exploit
None known
Authentication
Not required
EPSS
0.39% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Denial of Service
Impact
Denial Of Service
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
23 September 2026
Updated
15 October 2026
Weakness
CWE-1333

Vendor fix

Update to versions 3.30.15 or 4.3.1 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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