# CVE-2019-11049: mail() may release string with refcount==1 twice

> A double-free vulnerability in PHP's mail() function on Windows allows attackers to potentially execute arbitrary code or cause a denial of service.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/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:** 23 Dec 2019
- **Updated:** 16 Sep 2024
- **Also known as:** GHSA-h3jj-5ghg-r32j

## What is CVE-2019-11049?

CVE-2019-11049 is a medium-severity use after free vulnerability in Debian Debian Linux, published on 23 Dec 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In PHP versions 7.3.x below 7.3.13 and 7.4.0 on Windows, when supplying custom headers to mail() function, due to mistake introduced in commit 78f4b4a2dcf92ddbccea1bb95f8390a18ac3342e, if the header is supplied in lowercase, this can result in double-freeing certain memory locations.

Weakness: CWE-415 (Double Free)

## Which versions are affected by CVE-2019-11049?

It affects 4 products.


Products: Debian Debian Linux, Fedoraproject Fedora, Php Php, Tenable Security Center.

## How do I fix CVE-2019-11049?

Upgrade to a fixed version.

## Is CVE-2019-11049 being exploited?

There is no known exploitation of CVE-2019-11049 in the wild and no public exploit code.

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-11049 and fix it if it is affected.

What it is: CVE-2019-11049 is a medium-severity use after free vulnerability in Debian Debian Linux, published on 23 Dec 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-2019-11049 in the wild and no public exploit code.

Affected product: Debian Debian Linux. 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-2019-11049/ (Markdown: https://insights.sbomify.com/CVE-2019-11049/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-11049
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-11049
- OSV: https://osv.dev/vulnerability/CVE-2019-11049

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-11049/
Summaries are generated and may contain mistakes; the official description above is the record.