# CVE-2020-7065: mb_strtolower (UTF-32LE): stack-buffer-overflow at php_unicode_tolower_full

> A stack-buffer-overflow in PHP's mb_strtolower function with UTF-32LE encoding allows attackers to cause memory corruption, crashes, or potentially execute arbitrary code.

- **Severity:** High 7.4 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/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:** 1 Apr 2020
- **Updated:** 17 Sep 2024
- **Also known as:** BIT-libphp-2020-7065, BIT-php-2020-7065, BIT-php-min-2020-7065, DEBIAN-CVE-2020-7065, GHSA-hpqg-gp78-43q4, UBUNTU-CVE-2020-7065

## What is CVE-2020-7065?

CVE-2020-7065 is a high-severity memory corruption vulnerability in Canonical Ubuntu Linux, published on 1 Apr 2020. 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 7.3.16 and 7.4.x below 7.4.4, while using mb_strtolower() function with UTF-32LE encoding, certain invalid strings could cause PHP to overwrite stack-allocated buffer. This could lead to memory corruption, crashes and potentially code execution.

Weakness: CWE-787 (Out-of-bounds Write), CWE-121 (Stack-based Buffer Overflow)

## Which versions are affected by CVE-2020-7065?

3 open source packages ship an affected version, including libphp, php and php-min. It affects 4 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `libphp` | Bitnami | From 7.3.0 | 7.3.16, 7.4.4 |
| `php` | Bitnami | From 7.3.0 | 7.3.16, 7.4.4 |
| `php-min` | Bitnami | From 7.3.0 | 7.3.16, 7.4.4 |

Products: Canonical Ubuntu Linux, Debian Debian Linux, Php Php, Tenable Tenable.sc.

## How do I fix CVE-2020-7065?

Upgrade libphp to a fixed version for your release line: 7.3.16 or 7.4.4.

## Is CVE-2020-7065 being exploited?

There is no known exploitation of CVE-2020-7065 in the wild and no public exploit code.

## Other vulnerabilities in Canonical Ubuntu Linux

- [CVE-2020-11651](https://insights.sbomify.com/CVE-2020-11651/): SaltStack Salt Authentication Bypass (critical 9.8, exploited in the wild)
- [CVE-2020-7247](https://insights.sbomify.com/CVE-2020-7247/): OpenSMTPD Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2019-16928](https://insights.sbomify.com/CVE-2019-16928/): Exim Out-of-bounds Write (critical 9.8, exploited in the wild)
- [CVE-2018-6789](https://insights.sbomify.com/CVE-2018-6789/): Exim Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2015-2590](https://insights.sbomify.com/CVE-2015-2590/): Oracle Java SE and Java SE Embedded Remote Code Execution (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-7065 and fix it if it is affected.

What it is: CVE-2020-7065 is a high-severity memory corruption vulnerability in Canonical Ubuntu Linux, published on 1 Apr 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-2020-7065 in the wild and no public exploit code.

Affected packages and fixed versions:
- libphp (Bitnami): affected from 7.3.0; fixed in 7.3.16, 7.4.4
- php (Bitnami): affected from 7.3.0; fixed in 7.3.16, 7.4.4
- php-min (Bitnami): affected from 7.3.0; fixed in 7.3.16, 7.4.4

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-2020-7065/ (Markdown: https://insights.sbomify.com/CVE-2020-7065/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-7065
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-7065
- OSV: https://osv.dev/vulnerability/CVE-2020-7065

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-7065/
Summaries are generated and may contain mistakes; the official description above is the record.