# CVE-2019-19945: Integer overflow in n/a

> An attacker can crash the OpenWrt uhttpd web server by sending a crafted HTTP POST request with a negative Content-Length header.

- **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
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 16 Mar 2020
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-v643-533g-6c85

## What is CVE-2019-19945?

CVE-2019-19945 is a high-severity vulnerability in Openwrt Openwrt, published on 16 Mar 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

uhttpd in OpenWrt through 18.06.5 and 19.x through 19.07.0-rc2 has an integer signedness error. This leads to out-of-bounds access to a heap buffer and a subsequent crash. It can be triggered with an HTTP POST request to a CGI script, specifying both "Transfer-Encoding: chunked" and a large negative Content-Length value.

Weakness: CWE-681 (Incorrect Conversion between Numeric Types), CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2019-19945?

It affects 1 product.


Products: Openwrt Openwrt.

## How do I fix CVE-2019-19945?

No fix has been published for CVE-2019-19945 yet. Limit exposure of the affected software until one is available.

## Is CVE-2019-19945 being exploited?

There is no known exploitation of CVE-2019-19945 in the wild and no public exploit code.

Public exploit code:

- https://github.com/delicateByte/CVE-2019-19945_Test (github_poc): https://github.com/delicateByte/CVE-2019-19945_Test

## Other vulnerabilities in Openwrt Openwrt

- [CVE-2020-28951](https://insights.sbomify.com/CVE-2020-28951/): Use after free in n/a (critical 9.8)
- [CVE-2026-62948](https://insights.sbomify.com/CVE-2026-62948/): Cross-site scripting in openwrt (critical 9.6)
- [CVE-2026-30871](https://insights.sbomify.com/CVE-2026-30871/): OpenWrt Project has Stack-based Buffer Overflow in DNS PTR Query (critical 9.5)
- [CVE-2026-30872](https://insights.sbomify.com/CVE-2026-30872/): OpenWrt Project has a Stack-based Buffer Overflow vulnerability via IPv6 reverse DNS lookup (critical 9.5)
- [CVE-2021-28961](https://insights.sbomify.com/CVE-2021-28961/): Command injection in n/a (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-19945 and fix it if it is affected.

What it is: CVE-2019-19945 is a high-severity vulnerability in Openwrt Openwrt, published on 16 Mar 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2019-19945 in the wild and no public exploit code.

Affected product: Openwrt Openwrt. 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-2019-19945/ (Markdown: https://insights.sbomify.com/CVE-2019-19945/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-19945
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-19945
- OSV: https://osv.dev/vulnerability/CVE-2019-19945

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-19945/
Summaries are generated and may contain mistakes; the official description above is the record.