JLine: ReDoS in Nano Editor Regex Search Mode
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Partial Red Hat: 4 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-1333.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| jline | jline3 | 3.0.0 to before 3.30.15; 4.0.0 to before 4.3.1 | 3.30.15, 4.3.1 | Patch available | CNA |
| — | org.jline:jline-builtins (Maven) | 4.0.0 to before 4.3.1 | 4.3.1 | Patch available | GHSA-ph9c-7hw9-vhhw |
| — | org.jline:jline-builtins (Maven) | 3.0.0 to before 3.30.15 | 3.30.15 | Patch available | GHSA-ph9c-7hw9-vhhw |
- jline3 Vendorjline Affected 3.0.0 to before 3.30.15; 4.0.0 to before 4.3.1 Fixed in 3.30.15, 4.3.1 Patch available CNA
- org.jline:jline-builtins (Maven) Vendor— Affected 4.0.0 to before 4.3.1 Fixed in 4.3.1 Patch available GHSA-ph9c-7hw9-vhhw
- org.jline:jline-builtins (Maven) Vendor— Affected 3.0.0 to before 3.30.15 Fixed in 3.30.15 Patch available GHSA-ph9c-7hw9-vhhw
Remediation
- Fix · CNA jline3 (jline) Fixed in 3.30.15, 4.3.1
- Fix · GHSA-ph9c-7hw9-vhhw org.jline:jline-builtins (Maven) Fixed in 4.3.1 Advisory →
- Fix · GHSA-ph9c-7hw9-vhhw org.jline:jline-builtins (Maven) Fixed in 3.30.15 Advisory →
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat AMQ Broker 7 | Affected | No fix yet: Fix deferred |
| Red Hat Fuse 7 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift AI (RHOAI) | Affected | No fix yet: Fix deferred |
| Red Hat OpenStack Platform 13 (Queens) | Affected | No fix planned: Out of support scope |
Timeline
- 2026-10-02 Threatist record created from CVE-2026-77421
- 2026-10-03 Alias added: GHSA-ph9c-7hw9-vhhw
References
Other 8
- https://github.com/jline/jline3/security/advisories/GHSA-ph9c-7hw9-vhhw
- https://github.com/jline/jline3/pull/2012
- https://github.com/jline/jline3/pull/2018
- https://github.com/jline/jline3/commit/1d5fc3099e77938b971e197211cad2d4fbb17541
- https://github.com/jline/jline3/commit/341ee69ccc57b7733c1b40d6993219b64b3206ae
- https://github.com/jline/jline3/releases/tag/4.3.1
- https://github.com/jline/jline3/releases/tag/jline-3.30.15
- https://github.com/jline/jline3
More jline vulnerabilities
- TI-2026-54009 JLine: ReDoS in Built-in Less Viewer Search CVSS 3.1HIGH 7.5
- TI-2026-54008 JLine: ReDoS in Built-in grep Command Amplified by Automatic `.*` Wrapping CVSS 3.1HIGH 7.5
- TI-2026-40914 JLine: Unauthenticated Remote DoS via Unbounded Telnet NAWS Terminal Geometry CVSS 3.1HIGH 7.5
- TI-2026-40913 JLine: Unauthenticated Remote Memory Exhaustion via Unbounded Telnet NEW-ENVIRON Variables CVSS 3.1HIGH 7.5
- TI-2026-54006 JLine: ReDoS via `HISTORY_IGNORE` Configuration Variable CVSS 3.1MEDIUM 5.5
- TI-2023-27628 An issue in the component GroovyEngine.execute of jline-groovy v3.24.1 allows attackers… CVSS 3.1MEDIUM 5.5
Sources
- CVE-2026-77421 · CVE Program
- CVE-2026-77421 · NVD
- FIRST EPSS
- GHSA-ph9c-7hw9-vhhw · GitHub Advisory Database · CC BY 4.0
- CVE-2026-77421 · Red Hat security data · CC BY 4.0
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