# CVE-2020-1916: Integer overflow in HHVM

> An integer overflow in HHVM's ldap_escape function allows out-of-bounds writes, potentially enabling remote code execution.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/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:** No
- **Published:** 10 Mar 2021
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-37q2-jfrf-gv36, UBUNTU-CVE-2020-1916

## What is CVE-2020-1916?

CVE-2020-1916 is a critical vulnerability in Facebook HHVM, published on 10 Mar 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An incorrect size calculation in ldap_escape may lead to an integer overflow when overly long input is passed in, resulting in an out-of-bounds write. This issue affects HHVM prior to 4.56.2, all versions between 4.57.0 and 4.78.0, 4.79.0, 4.80.0, 4.81.0, 4.82.0, 4.83.0.

Weakness: CWE-787 (Out-of-bounds Write), CWE-122 (Heap-based Buffer Overflow)

## Which versions are affected by CVE-2020-1916?

It affects 1 product.


Products: Facebook Hhvm.

## How do I fix CVE-2020-1916?

No fix has been published for CVE-2020-1916 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-1916 being exploited?

There is no known exploitation of CVE-2020-1916 in the wild and no public exploit code.

## Other vulnerabilities in Facebook HHVM

- [CVE-2022-36937](https://insights.sbomify.com/CVE-2022-36937/): HHVM 4.172.0 and all prior versions use TLS 1.0 for secure connections when handling tls:// URLs in the stream extension. (critical 9.8)
- [CVE-2020-1900](https://insights.sbomify.com/CVE-2020-1900/): Use after free in HHVM (critical 9.8)
- [CVE-2020-1917](https://insights.sbomify.com/CVE-2020-1917/): Memory corruption in HHVM (critical 9.8)
- [CVE-2021-24025](https://insights.sbomify.com/CVE-2021-24025/): Integer overflow in HHVM (critical 9.8)
- [CVE-2016-1000004](https://insights.sbomify.com/CVE-2016-1000004/): Other in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-1916 and fix it if it is affected.

What it is: CVE-2020-1916 is a critical vulnerability in Facebook HHVM, published on 10 Mar 2021. 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-2020-1916 in the wild and no public exploit code.

Affected product: Facebook HHVM. 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-2020-1916/ (Markdown: https://insights.sbomify.com/CVE-2020-1916/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-1916
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-1916
- OSV: https://osv.dev/vulnerability/CVE-2020-1916

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-1916/
Summaries are generated and may contain mistakes; the official description above is the record.