# CVE-2026-116795: RE2JS: Quadratic-time denial of service in re2js lookbehind matching


- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 28 Oct 2026
- **Updated:** 28 Oct 2026
- **Also known as:** ECHO-3abd-6fdf-e676, GHSA-gg6h-894w-4m9c

## What is CVE-2026-116795?

CVE-2026-116795 is a high-severity vulnerability in le0pard re2js, published on 28 Oct 2026. 

### Official description

RE2JS is the JavaScript port of RE2, a regular expression engine that provides linear time matching. From 2.2.0 until 2.8.7, enabling LOOKBEHINDS and using repeated matching through matcher().find(), matchAll(), split(), or matcher().replaceAll() can cause quadratic total work. Machine.match restarts lookbehind scanning from offset zero for each requested start position, while Matcher-based APIs request capture slots that prevent the early exit used for captureless matching. Dense matches therefore repeatedly rescan the input, allowing attacker-influenced text to monopolize a single-threaded worker and deny service. This issue is fixed in version 2.8.7.

Weakness: CWE-407 (Inefficient Algorithmic Complexity), CWE-1333 (Inefficient Regular Expression Complexity)

## Which versions are affected by CVE-2026-116795?

2 open source packages ship an affected version, including re2js.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `re2js` | npm | From 2.2.0 | 2.8.7 |
| `re2js` | npm | From 2.2.0 | 2.8.7 |

## How do I fix CVE-2026-116795?

Upgrade re2js to 2.8.7 or later.

## Is CVE-2026-116795 being exploited?

There is no known exploitation of CVE-2026-116795 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-116795 and fix it if it is affected.

What it is: CVE-2026-116795 is a high-severity vulnerability in le0pard re2js, published on 28 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-116795 in the wild and no public exploit code.

Affected packages and fixed versions:
- re2js (npm): affected from 2.2.0; fixed in 2.8.7
- re2js (npm): affected from 2.2.0; fixed in 2.8.7

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-116795/ (Markdown: https://insights.sbomify.com/CVE-2026-116795/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-116795
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-116795
- OSV: https://osv.dev/vulnerability/CVE-2026-116795

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-116795/
Summaries are generated and may contain mistakes; the official description above is the record.