5.5

CVE-2026-77420: JLine: ReDoS via `HISTORY_IGNORE` Configuration Variable

Awaiting analysis
AliasesUBUNTU-CVE-2026-77420DEBIAN-CVE-2026-77420CGA-29hg-fjgq-vgg4
Published 23-09-2026Last modified 29-09-2026

Vulnerability summary

CVE-2026-77420 is a medium (CVSS 5.5) vulnerability in jline jline3. EPSS estimates a 0.18% chance of exploitation in the next 30 days, higher than 7.7% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 5.5, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
5.5/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.18%
0%100%
Low · +0.06 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. 29-09-2026
    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, DefaultHistory.matchPatterns(String patterns, String line) in reader/src/main/java/org/jline/reader/impl/history/DefaultHistory.java converts the HISTORY_IGNORE configuration value into a Java regular expression while escaping only part of its syntax, allowing other regex metacharacters to reach the backtracking engine. An attacker who can control application or user configuration can supply a nested-quantifier expression that is reevaluated whenever a command is added to history, consuming excessive CPU and indefinitely blocking the reader thread. This issue is fixed in versions 3.30.15 and 4.3.1.

CVSS metrics

7 scores · 7 sources · 1 version

EPSS trend

Probability

0.18%

Chance of exploitation in the next 30 days

Percentile

8%

Versus all other CVEs

30-day change

Increase +0.06 pp

From 0.12% 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: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Chainguard84 products
  • akhq< 0.28.0-r9
  • apache-camel-karavan-devmode< 4.18.1-r13
  • apache-nifi-2.11< 2.11.0-r9
  • apache-polarisAll versions (No fix recorded)
  • apache-polaris-fipsAll versions (No fix recorded)
Wolfi16 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-reader≥ 4.0.0, < 4.3.1 | ≥ 3.0.0, < 3.30.15

6 vendors · 106 products

References

13 links
Show all 13 references