Answer in brief
CVE-2026-77421 records a Medium severity (CVSS 6.5) vulnerability in JLine: ReDoS in Nano Editor Regex Search Mode. The current sources do not mark it as known exploited. The current feed maps jline/jline3 (generic), org.jline:jline-builtins (maven), org.jline:jline-builtins (maven), org.jline:jline-builtins (maven) and additional mapped packages. Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 6.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps jline/jline3 (generic), org.jline:jline-builtins (maven), org.jline:jline-builtins (maven), org.jline:jline-builtins (maven) and additional mapped packages. Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| jline/jline3generic | >=3.0.0 <3.30.15 || >=4.0.0 <4.3.1 | 3.30.15, 4.3.1 |
| org.jline:jline-builtinsmaven | >=3.0.0 <3.30.15 | 3.30.15 |
| org.jline:jline-builtinsmaven | >=4.0.0,<4.3.1 | 4.3.1 |
| org.jline:jline-builtinsmaven | >=3.0.0,<3.30.15 | 3.30.15 |
| org.jline:jline-builtinsmaven | >=4.0.0 <4.3.1 | 4.3.1 |
Published upstream
Sep 23, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 23, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Sep 23, 2026
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.
Quoted source text, attributed separately from HOL analysis.