# JLine: ReDoS via \`HISTORY_IGNORE\` Configuration Variable

Advisory record · `GHSA-5q95-hrpc-m3w3`

- **Identifiers:** `GHSA-5q95-hrpc-m3w3` · `CVE-2026-77420`
- **State:** Confirmed
- **Severity:** CVSS 5.5 Medium
- **Critical:** No
- **Weakness (CWE):** [CWE-1333](https://cwe.mitre.org/data/definitions/1333.html)
- **Tags:** [Denial of service](https://agentprime.io/advisories/tag/dos.md)
- **Published:** 23 Sept 2026
- **Updated:** 23 Sept 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 23 Sept 2026, 18:12 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `org.jline:jline-reader` (Maven): affected `>=4.0.0, <4.3.1 || >=3.0.0, <3.30.15`; fixed in `4.3.1`, `3.30.15`

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> Versions of org.jline:jline-reader from 3.0.0 before 3.30.15 and from 4.0.0 before 4.3.1 are affected. Where the HISTORY_IGNORE setting is supplied through user configuration or application settings, a crafted value containing regex metacharacters can cause catastrophic backtracking when a line is added to history, hanging the reader thread at high CPU. Upgrade to 3.30.15 or 4.3.1, or later. Avoid letting untrusted users set HISTORY_IGNORE.

Written 2 Nov 2026.

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 5.5 Medium, CVSS 3.1: `CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`, from CNA (GitHub_M)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0018, the 7th percentile, on 7 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:16 UTC: First seen by agentprime
- 31 Oct 2026, 14:16 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-5q95-hrpc-m3w3)

## Sources

- [GitHub Advisory Database: GHSA-5q95-hrpc-m3w3](https://github.com/advisories/GHSA-5q95-hrpc-m3w3)
- [OSV: GHSA-5q95-hrpc-m3w3](https://osv.dev/vulnerability/GHSA-5q95-hrpc-m3w3)
- <https://github.com/jline/jline3/security/advisories/GHSA-5q95-hrpc-m3w3>
- <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>
- <https://github.com/jline/jline3/releases/tag/4.3.1>
- <https://github.com/jline/jline3/releases/tag/jline-3.30.15>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-5q95-hrpc-m3w3>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-5q95-hrpc-m3w3/>. Everything for agents: <https://agentprime.io/llms.txt>.