6.5

CVE-2026-77421: JLine: ReDoS in Nano Editor Regex Search Mode

Awaiting analysis
AliasesUBUNTU-CVE-2026-77421DEBIAN-CVE-2026-77421CGA-2p2h-gm5g-7vp7
Published 23-09-2026Last modified 23-09-2026

Vulnerability summary

CVE-2026-77421 is a medium (CVSS 6.5) vulnerability in jline jline3. EPSS estimates a 0.43% chance of exploitation in the next 30 days, higher than 37.7% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 6.5, network access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
6.5/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.43%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Timeline

  1. 23-09-2026
    PublishedVulnerability first disclosed.
  2. 23-09-2026
    Last modifiedVulnerability information updated.

Description

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.

CVSS metrics

7 scores · 7 sources · 1 version

EPSS trend

Probability

0.43%

Chance of exploitation in the next 30 days

Percentile

38%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.43% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Chainguard52 products
  • akhq< 0.28.0-r9
  • apache-camel-karavan-devmode< 4.18.1-r13
  • apache-nifi-2.11< 2.11.0-r8
  • apache-polarisAll versions (No fix recorded)
  • apache-polaris-fipsAll versions (No fix recorded)
Wolfi11 products
  • akhq< 0.28.0-r9
  • apache-pulsar-4.2< 4.2.4-r6
  • celeborn-0.6All versions (No fix recorded)
  • druid< 37.0.0-r60
  • kafka-4.1< 4.1.2-r9
Ubuntu3 products
  • jlineAll versions (No fix recorded)
  • jline2All versions (No fix recorded)
  • jline3All versions (No fix recorded)
Debian1 product
  • jline3All versions (No fix recorded)
Jline1 product
  • jline3≥ 3.0.0, < 3.30.15 | ≥ 4.0.0, < 4.3.1
Org.jline1 product
  • jline-builtins≥ 4.0.0, < 4.3.1 | ≥ 3.0.0, < 3.30.15

6 vendors · 69 products

References

13 links
Show all 13 references