# CVE-2019-19203: Memory corruption in n/a

> A heap-based buffer over-read in the Oniguruma regex library allows attackers to cause denial of service or disclose sensitive memory contents.

- **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:** Yes
- **Published:** 21 Nov 2019
- **Updated:** 5 Aug 2024
- **Also known as:** CLSA-2026-1776951056, DEBIAN-CVE-2019-19203, GHSA-ggp4-f63c-mcc4, UBUNTU-CVE-2019-19203

## What is CVE-2019-19203?

CVE-2019-19203 is a high-severity memory corruption vulnerability in Fedoraproject Fedora, published on 21 Nov 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An issue was discovered in Oniguruma 6.x before 6.9.4_rc2. In the function gb18030_mbc_enc_len in file gb18030.c, a UChar pointer is dereferenced without checking if it passed the end of the matched string. This leads to a heap-based buffer over-read.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2019-19203?

It affects 2 products.


Products: Fedoraproject Fedora, Oniguruma Project Oniguruma.

## How do I fix CVE-2019-19203?

Upgrade to a fixed version.

## Is CVE-2019-19203 being exploited?

There is no known exploitation of CVE-2019-19203 in the wild and no public exploit code.

Public exploit code:

- Heap-buffer-overflow in Oniguruma (function gb18030_mbc_enc_len) (github_poc): https://github.com/ManhNDd/CVE-2019-19203
- An issue was discovered in Oniguruma 6.x before 6.9.4_rc2. In the function gb18030_mbc_enc_len in file gb18030.c, a UChar pointer is dereferenced without checking if it passed the end of the matched string. This leads to a heap-based buffer over-read (github_poc): https://github.com/tarantula-team/CVE-2019-19203

## Other vulnerabilities in Fedoraproject Fedora

- [CVE-2024-4577](https://insights.sbomify.com/CVE-2024-4577/): PHP-CGI OS Command Injection (critical 9.8, exploited in the wild)
- [CVE-2021-39226](https://insights.sbomify.com/CVE-2021-39226/): Grafana Authentication Bypass (critical 9.8, exploited in the wild)
- [CVE-2019-5544](https://insights.sbomify.com/CVE-2019-5544/): VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2024-4947](https://insights.sbomify.com/CVE-2024-4947/): Google Chromium V8 Type Confusion (critical 9.6, exploited in the wild)
- [CVE-2024-4671](https://insights.sbomify.com/CVE-2024-4671/): Google Chromium Visuals Use-After-Free (critical 9.6, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-19203 and fix it if it is affected.

What it is: CVE-2019-19203 is a high-severity memory corruption vulnerability in Fedoraproject Fedora, published on 21 Nov 2019. 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-2019-19203 in the wild and no public exploit code.

Affected product: Fedoraproject Fedora. 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-2019-19203/ (Markdown: https://insights.sbomify.com/CVE-2019-19203/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-19203
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-19203
- OSV: https://osv.dev/vulnerability/CVE-2019-19203

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-19203/
Summaries are generated and may contain mistakes; the official description above is the record.