Skip to content
Fencer Vulns
medium 6.5

CVE-2026-77421 json

JLine: ReDoS in Nano Editor Regex Search Mode

published 2026-09-23 46 d ago modified 2026-09-30 40 d ago also EUVD-2026-85522 , GHSA-ph9c-7hw9-vhhw

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 37%
public exploits
0
none known

Summary

JLine is a Java library for handling console input. From 3.0.0 until 3.30.15 and 4.3.1, the JLine built-in nano editor's regex search mode passes a user-controlled search term from doSearch(String text) in builtins/src/main/java/org/jline/builtins/Nano.java to Java's backtracking regular expression engine without a timeout or backtracking bound. A nested-quantifier expression evaluated against non-matching buffer content can consume excessive CPU and indefinitely block the editor session thread, and remote multi-user deployments can lose a worker thread for each affected session. This issue is fixed in versions 3.30.15 and 4.3.1.

Patch / fix

  • maven org.jline:jline-builtins 3.30.15, 4.3.1
  • jline jline 3.30.15, 4.3.1
  • org.jline jline-builtins 3.30.15, 4.3.1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-77421 updated cvss 5.7

org.jline/jline-builtins: JLine: Denial of Service in Nano Editor Regex Search

  • Red Hat AMQ Broker 7 jline-reader, jline-builtins 3.30.8.redhat-00001
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Fuse 7 jline-reader, jline-builtins 3.30.8.redhat-00001
    affected: workaround, no fix available, no fix planned “Out of support scope”
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-spark-operator-rhel9, rhoai/odh-th-torch-cpu-py312-rhel9, rhoai/odh-th-torch-cuda-py312-rhel9, rhoai/odh-th06-cpu-torch210-py312-rhel9, rhoai/odh-th06-cpu-torch291-py312-rhel9, rhoai/odh-th06-rocm64-torch291-py312-rhel9, +2 more
    affected: workaround, no fix available “Fix deferred”
  • Red Hat OpenStack Platform 13 (Queens) opendaylight
    affected: workaround, no fix planned “Out of support scope”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
46 d ago

Exploit prediction

0.43% chance of exploitation in the next 30 days, higher than 37% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
GitHub 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
maven org.jline:jline-builtins
>=4.0.0, <4.3.1
>=3.0.0, <3.30.15
4.3.1
3.30.15

Affected products

  • jline jline3

Classification

Weakness
  • CWE-1333 Inefficient Regular Expression Complexity

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.