7.5

CVE-2026-77423: JLine: ReDoS in Built-in Less Viewer Search

Awaiting analysis
AliasesUBUNTU-CVE-2026-77423DEBIAN-CVE-2026-77423
Published 23-09-2026Last modified 24-09-2026

Vulnerability summary

CVE-2026-77423 is a high (CVSS 7.5) vulnerability in jline jline3. EPSS estimates a 0.46% chance of exploitation in the next 30 days, higher than 40% of scored vulnerabilities.

Priority
Prioritisesevere

Severe, CVSS 7.5 (CVE.org); no exploitation reported by the 5 checked sources; EPSS 0% (FIRST, 03-11-2026)

Source freshness unavailable

How is this decided?
CVSS score
7.5/10
010
High · v3.1 (CVE.org)
EPSS score
0.46%
0%100%
Low · +0.08 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. 24-09-2026
    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 less viewer passes user-controlled search and display-filter patterns from getPattern(boolean doDisplayPattern) in builtins/src/main/java/org/jline/builtins/Less.java directly to Java's backtracking regular expression engine and repeatedly applies them to file content. A nested-quantifier expression evaluated against non-matching lines can consume excessive CPU and indefinitely block the session thread, and repeated sessions in Telnet or SSH deployments can exhaust a bounded worker pool. This issue is fixed in versions 3.30.15 and 4.3.1.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.46%

Chance of exploitation in the next 30 days

Percentile

40%

Versus all other CVEs

30-day change

Increase +0.08 pp

From 0.39% 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, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

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

3 vendors · 5 products

References

10 links