# CVE-2026-103043: anchorme through 3.0.8 Regular Expression Denial of Service

> Attackers can cause denial of service in applications using the anchorme library by submitting crafted input that triggers catastrophic regex backtracking.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 29 Sep 2026
- **Updated:** 20 Oct 2026
- **Also known as:** GHSA-phc2-88rx-x2mp

## What is CVE-2026-103043?

CVE-2026-103043 is a high-severity denial of service vulnerability in alexcorvi anchorme, published on 29 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

anchorme through 3.0.8 contains a regular expression denial of service vulnerability in the IPv6 host extraction regex due to catastrophic backtracking. Attackers can supply specially crafted input strings with repeated patterns to cause exponential regex engine backtracking, blocking the Node.js event loop and denying service to other requests.

Weakness: CWE-1333 (Inefficient Regular Expression Complexity)

## Which versions are affected by CVE-2026-103043?


## How do I fix CVE-2026-103043?

No fix has been published for CVE-2026-103043 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-103043 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-103043 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-103043 and fix it if it is affected.

What it is: CVE-2026-103043 is a high-severity denial of service vulnerability in alexcorvi anchorme, published on 29 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-103043 exists.

Affected product: alexcorvi anchorme. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2026-103043/ (Markdown: https://insights.sbomify.com/CVE-2026-103043/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-103043
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-103043
- OSV: https://osv.dev/vulnerability/CVE-2026-103043

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-103043/
Summaries are generated and may contain mistakes; the official description above is the record.