CVE-2026-77420: jline jline3 · ReDoS
Affects jline jline3Source CVE Database V5
Not known to be exploited · CVSS 5.5 Medium : upgrade to 4.3.1 or 3.30.15 when convenient.
Data as of 7 Nov 2026, 23:24 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 7% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 4.3.1, 3.30.15
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 23 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 7 Nov 2026.
What to do
Upgrade jline3 and org.jline/jline3 to 4.3.1 or 3.30.15.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| jlinejline3 | Affected
| Fixed in
|
| jlinejline3 | Affected
| Fixed in
|
Mavenorg.jline/jline3pkg:maven/org.jline/jline3Other threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
This vulnerability is fixed in jline3 versions 3.30.15 and 4.3.1. Users should upgrade to these or later versions to remediate the issue. No other mitigations are indicated by the vendor advisory.
Description
CVE-2026-77420 is a medium severity vulnerability in the jline3 Java library affecting versions from 3.0.0 up to but not including 3.30.15 and from 4.0.0 up to but not including 4.3.1. The flaw arises from inefficient regular expression handling in the DefaultHistory.matchPatterns method, where partial escaping of regex syntax allows nested quantifiers to cause excessive CPU consumption and indefinite blocking of the reader thread. This can be triggered by an attacker controlling application or user configuration. The issue is fixed in versions 3.30.15 and 4.3.1.
References
- github.com/jline/jline3/security/advisories/GHSA-5q95-hrpc-m3w3 (opens in a new tab)
- github.com/jline/jline3/pull/2012 (opens in a new tab)
- github.com/jline/jline3/pull/2018 (opens in a new tab)
- github.com/jline/jline3/commit/1d5fc3099e77938b971e197211cad2d4fbb17541 (opens in a new tab)
- github.com/jline/jline3/commit/341ee69ccc57b7733c1b40d6993219b64b3206ae (opens in a new tab)
- github.com/jline/jline3/releases/tag/4.3.1 (opens in a new tab)
- github.com/jline/jline3/releases/tag/jline-3.30.15 (opens in a new tab)