CVE catalog
CVE-2026-55204
HAProxy through 3.4.0, fixed in commit 9a6d1fe, contains a null pointer dereference vulnerability in hpack_dht_insert() within src/hpack-tbl.c that fails to validate the return value of hpack_dht_def
- Severity
- High · CVSS 8.7
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - Published
- Source
- [NVD] · [CVE record]
- EPSS
- 0.48% · Oct 25, 2026
HAProxy through 3.4.0, fixed in commit 9a6d1fe, contains a null pointer dereference vulnerability in hpack_dht_insert() within src/hpack-tbl.c that fails to validate the return value of hpack_dht_defrag() when the memory pool is exhausted. An attacker can trigger HPACK dynamic table insertions under memory pressure to dereference a NULL pointer and crash HAProxy worker processes, causing denial of service.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | haproxy | sid | 3.2.26-1 | fixed |
| Debian | haproxy | forky | 3.2.26-1 | fixed |
| Debian | haproxy | trixie | 3.0.11-1+deb13u3 | vulnerable |
| Debian | haproxy | trixie-security | 3.0.11-1+deb13u4 | vulnerable |
| Debian | haproxy | bookworm | 2.6.12-1+deb12u3 | vulnerable |
| Debian | haproxy | bookworm-security | 2.6.12-1+deb12u4 | vulnerable |
| Cpe | haproxy | Not reported | 2.8.16-0ubuntu0.24.04.3 | fixed |
| Cpe | haproxy-doc | Not reported | 2.8.16-0ubuntu0.24.04.3 | fixed |
| Cpe | vim-haproxy | Not reported | 2.8.16-0ubuntu0.24.04.3 | fixed |
| Cpe | haproxy | Not reported | Not reported | vulnerable |
| Cpe | haproxy | Not reported | Not reported | unknown |
| Cpe | haproxy | Not reported | 3.4.1 | fixed |
| Ubuntu | haproxy | pro | 1.7.9-1ubuntu1 | vulnerable |
| Ubuntu | haproxy | pro | 1.7.9-1ubuntu2 | vulnerable |
| Ubuntu | haproxy | pro | 1.8.4-1 | vulnerable |
| Ubuntu | haproxy | pro | 1.8.7-1 | vulnerable |
| Ubuntu | haproxy | pro | 1.8.8-1 | vulnerable |
| Ubuntu | haproxy | pro | 1.8.8-1ubuntu0.1 | vulnerable |
| Ubuntu | haproxy | pro | 1.8.8-1ubuntu0.2 | vulnerable |
| Ubuntu | haproxy | pro | 1.8.8-1ubuntu0.3 | vulnerable |
| Ubuntu | haproxy | pro | 1.8.8-1ubuntu0.4 | vulnerable |
| Ubuntu | haproxy | pro | 1.8.8-1ubuntu0.6 | vulnerable |
| Ubuntu | haproxy | pro | 1.8.8-1ubuntu0.7 | vulnerable |
| Ubuntu | haproxy | pro | 1.8.8-1ubuntu0.8 | vulnerable |
| Ubuntu | haproxy | pro | 1.8.8-1ubuntu0.9 | vulnerable |
| Ubuntu | haproxy | pro | 1.8.8-1ubuntu0.10 | vulnerable |
| Ubuntu | haproxy | pro | 1.8.8-1ubuntu0.11 | vulnerable |
| Ubuntu | haproxy | pro | 1.8.8-1ubuntu0.13 | vulnerable |
| Ubuntu | haproxy | pro | 1.8.8-1ubuntu0.13+esm2 | vulnerable |
| Ubuntu | haproxy | pro | 1.8.8-1ubuntu0.13+esm3 | vulnerable |
| Ubuntu | haproxy | 20.04 | 2.0.5-1 | vulnerable |
| Ubuntu | haproxy | 20.04 | 2.0.8-1 | vulnerable |
| Ubuntu | haproxy | 20.04 | 2.0.9-1 | vulnerable |
| Ubuntu | haproxy | 20.04 | 2.0.10-1 | vulnerable |
| Ubuntu | haproxy | 20.04 | 2.0.10-1ubuntu1 | vulnerable |
| Ubuntu | haproxy | 20.04 | 2.0.11-1ubuntu1 | vulnerable |
| Ubuntu | haproxy | 20.04 | 2.0.12-1ubuntu2 | vulnerable |
| Ubuntu | haproxy | 20.04 | 2.0.13-1ubuntu2 | vulnerable |
| Ubuntu | haproxy | 20.04 | 2.0.13-2 | vulnerable |
| Ubuntu | haproxy | 20.04 | 2.0.13-2ubuntu0.1 | vulnerable |
| Ubuntu | haproxy | 20.04 | 2.0.13-2ubuntu0.2 | vulnerable |
| Ubuntu | haproxy | 20.04 | 2.0.13-2ubuntu0.3 | vulnerable |
| Ubuntu | haproxy | 20.04 | 2.0.13-2ubuntu0.5 | vulnerable |
| Ubuntu | haproxy | 20.04 | 2.0.29-0ubuntu1 | vulnerable |
| Ubuntu | haproxy | 20.04 | 2.0.29-0ubuntu1.1 | vulnerable |
| Ubuntu | haproxy | 20.04 | 2.0.29-0ubuntu1.3 | vulnerable |
| Ubuntu | haproxy | 20.04 | 2.0.31-0ubuntu0.1 | vulnerable |
| Ubuntu | haproxy | 20.04 | 2.0.31-0ubuntu0.2 | vulnerable |
| Ubuntu | haproxy | 20.04 | 2.0.31-0ubuntu0.3 | vulnerable |
| Ubuntu | haproxy | 20.04 | 2.0.33-0ubuntu0.1 | vulnerable |
| Ubuntu | haproxy | 22.04 | 2.2.9-2ubuntu2 | vulnerable |
| Ubuntu | haproxy | 22.04 | 2.4.8-1 | vulnerable |
| Ubuntu | haproxy | 22.04 | 2.4.8-2ubuntu3 | vulnerable |
| Ubuntu | haproxy | 22.04 | 2.4.11-1ubuntu1 | vulnerable |
| Ubuntu | haproxy | 22.04 | 2.4.12-1ubuntu1 | vulnerable |
| Ubuntu | haproxy | 22.04 | 2.4.12-1ubuntu2 | vulnerable |
| Ubuntu | haproxy | 22.04 | 2.4.13-1ubuntu1 | vulnerable |
| Ubuntu | haproxy | 22.04 | 2.4.14-1ubuntu1 | vulnerable |
| Ubuntu | haproxy | 22.04 | 2.4.18-0ubuntu1 | vulnerable |
| Ubuntu | haproxy | 22.04 | 2.4.18-0ubuntu1.1 | vulnerable |
| Ubuntu | haproxy | 22.04 | 2.4.18-0ubuntu1.2 | vulnerable |
| Ubuntu | haproxy | 22.04 | 2.4.18-0ubuntu1.3 | vulnerable |
| Ubuntu | haproxy | 22.04 | 2.4.22-0ubuntu0.22.04.1 | vulnerable |
| Ubuntu | haproxy | 22.04 | 2.4.22-0ubuntu0.22.04.2 | vulnerable |
| Ubuntu | haproxy | 22.04 | 2.4.22-0ubuntu0.22.04.3 | vulnerable |
| Ubuntu | haproxy | 22.04 | 2.4.24-0ubuntu0.22.04.1 | vulnerable |
| Ubuntu | haproxy | 22.04 | 2.4.24-0ubuntu0.22.04.2 | vulnerable |
| Ubuntu | haproxy | 22.04 | 2.4.24-0ubuntu0.22.04.3 | vulnerable |
| Ubuntu | haproxy | 22.04 | 2.4.29-0ubuntu0.22.04.1 | vulnerable |
| Ubuntu | haproxy | 22.04 | 2.4.30-0ubuntu0.22.04.1 | vulnerable |
| Ubuntu | haproxy | 22.04 | 2.4.30-0ubuntu0.22.04.2 | fixed |
| Ubuntu | haproxy | 24.04 | 2.6.15-1ubuntu2 | vulnerable |
| Ubuntu | haproxy | 24.04 | 2.8.5-1ubuntu1 | vulnerable |
| Ubuntu | haproxy | 24.04 | 2.8.5-1ubuntu2 | vulnerable |
| Ubuntu | haproxy | 24.04 | 2.8.5-1ubuntu3 | vulnerable |
| Ubuntu | haproxy | 24.04 | 2.8.5-1ubuntu3.1 | vulnerable |
| Ubuntu | haproxy | 24.04 | 2.8.5-1ubuntu3.2 | vulnerable |
| Ubuntu | haproxy | 24.04 | 2.8.5-1ubuntu3.3 | vulnerable |
| Ubuntu | haproxy | 24.04 | 2.8.5-1ubuntu3.4 | vulnerable |
| Ubuntu | haproxy | 24.04 | 2.8.15-0ubuntu0.24.04.1 | vulnerable |
| Ubuntu | haproxy | 24.04 | 2.8.16-0ubuntu0.24.04.1 | vulnerable |
| Ubuntu | haproxy | 24.04 | 2.8.16-0ubuntu0.24.04.2 | vulnerable |
| Ubuntu | haproxy | 24.04 | 2.8.16-0ubuntu0.24.04.3 | fixed |
| Ubuntu | haproxy | 25.10 | 3.0.8-1ubuntu1 | vulnerable |
| Ubuntu | haproxy | 25.10 | 3.0.8-1ubuntu1.1 | vulnerable |
| Ubuntu | haproxy | 25.10 | 3.0.10-1ubuntu1 | vulnerable |
| Ubuntu | haproxy | 25.10 | 3.0.10-1ubuntu2 | vulnerable |
| Ubuntu | haproxy | 25.10 | 3.0.10-1ubuntu3 | vulnerable |
| Ubuntu | haproxy | 25.10 | 3.0.12-0ubuntu0.25.10.1 | vulnerable |
| Ubuntu | haproxy | 25.10 | 3.0.12-0ubuntu0.25.10.3 | vulnerable |
| Ubuntu | haproxy | 25.10 | 3.0.12-0ubuntu0.25.10.4 | vulnerable |
| Ubuntu | haproxy | 25.10 | 3.0.12-0ubuntu0.25.10.5 | fixed |
| Ubuntu | haproxy | 26.04 | 3.0.10-1ubuntu3 | vulnerable |
| Ubuntu | haproxy | 26.04 | 3.2.9-1ubuntu1 | vulnerable |
| Ubuntu | haproxy | 26.04 | 3.2.9-1ubuntu2 | vulnerable |
| Ubuntu | haproxy | 26.04 | 3.2.9-1ubuntu2.1 | vulnerable |
| Ubuntu | haproxy | 26.04 | 3.2.9-1ubuntu2.2 | fixed |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | haproxy | source | sid | 3.2.20-1 | not yet assigned | Not reported | [1140430] |
| Debian | haproxy | source | forky | 3.2.20-1 | not yet assigned | Not reported | [1140430] |
| Debian | haproxy | source | trixie | (unfixed) | not yet assigned | Not reported | [1140430] |
| Debian | haproxy | source | bookworm | (unfixed) | not yet assigned | Not reported | [1140430] |
| Cpe | haproxy | cpe | Not reported | 2.8.16-0ubuntu0.24.04.3 | Not reported | Not reported | Not reported |
| Cpe | haproxy-doc | cpe | Not reported | 2.8.16-0ubuntu0.24.04.3 | Not reported | Not reported | Not reported |
| Cpe | vim-haproxy | cpe | Not reported | 2.8.16-0ubuntu0.24.04.3 | Not reported | Not reported | Not reported |
| Cpe | haproxy | cpe | Not reported | 3.4.1 | Not reported | NVD-CVE-2026-55204 | Not reported |
| Ubuntu | haproxy | deb | 22.04 | 2.4.30-0ubuntu0.22.04.2 | Not reported | UBUNTU-CVE-2026-55204 | Not reported |
| Ubuntu | haproxy | deb | 24.04 | 2.8.16-0ubuntu0.24.04.3 | Not reported | UBUNTU-CVE-2026-55204 | Not reported |
| Ubuntu | haproxy | deb | 25.10 | 3.0.12-0ubuntu0.25.10.5 | Not reported | UBUNTU-CVE-2026-55204 | Not reported |
| Ubuntu | haproxy | deb | 26.04 | 3.2.9-1ubuntu2.2 | Not reported | UBUNTU-CVE-2026-55204 | Not reported |
Notes
[trixie] haproxy: Minor issue [bookworm] haproxy: Minor issue
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [haproxy]Affected
Details (4)
2.6.12-1+deb12u3· amd64 · bookwormAffected
nvd · haproxy · debian · bookworm; nvd · haproxy · debian · 12
2.6.12-1+deb12u3· arm64 · bookwormAffected
nvd · haproxy · debian · bookworm; nvd · haproxy · debian · 12
2.6.12-1+deb12u3· amd64 · bookworm-securityAffected
nvd · haproxy · debian · bookworm; nvd · haproxy · debian · 12
2.6.12-1+deb12u3· arm64 · bookworm-securityAffected
nvd · haproxy · debian · bookworm; nvd · haproxy · debian · 12
- [haproxy-doc]Affected
Source package: [haproxy]
Details (4)
2.6.12-1+deb12u3· all · bookwormAffected
nvd · haproxy · debian · bookworm; nvd · haproxy · debian · 12
2.6.12-1+deb12u3· all · bookwormAffected
nvd · haproxy · debian · bookworm; nvd · haproxy · debian · 12
2.6.12-1+deb12u3· all · bookworm-securityAffected
nvd · haproxy · debian · bookworm; nvd · haproxy · debian · 12
2.6.12-1+deb12u3· all · bookworm-securityAffected
nvd · haproxy · debian · bookworm; nvd · haproxy · debian · 12
- [vim-haproxy]Affected
Source package: [haproxy]
Details (4)
2.6.12-1+deb12u3· all · bookwormAffected
nvd · haproxy · debian · bookworm; nvd · haproxy · debian · 12
2.6.12-1+deb12u3· all · bookwormAffected
nvd · haproxy · debian · bookworm; nvd · haproxy · debian · 12
2.6.12-1+deb12u3· all · bookworm-securityAffected
nvd · haproxy · debian · bookworm; nvd · haproxy · debian · 12
2.6.12-1+deb12u3· all · bookworm-securityAffected
nvd · haproxy · debian · bookworm; nvd · haproxy · debian · 12
[Debian 13 (Trixie)]
- [haproxy]Affected
Details (5)
3.0.11-1+deb13u3· amd64 · trixieAffected
nvd · haproxy · debian · 13
3.0.11-1+deb13u3· arm64 · trixieAffected
nvd · haproxy · debian · 13
3.0.11-1+deb13u3· amd64 · trixie-security · Historical versionAffected
nvd · haproxy · debian · 13
3.0.11-1+deb13u3· arm64 · trixie-securityAffected
nvd · haproxy · debian · 13
3.0.11-1+deb13u4· amd64 · trixie-securityAffected
nvd · haproxy · debian · 13
- [haproxy-doc]Affected
Source package: [haproxy]
Details (5)
3.0.11-1+deb13u3· all · trixieAffected
nvd · haproxy · debian · 13
3.0.11-1+deb13u3· all · trixieAffected
nvd · haproxy · debian · 13
3.0.11-1+deb13u3· all · trixie-securityAffected
nvd · haproxy · debian · 13
3.0.11-1+deb13u3· all · trixie-security · Historical versionAffected
nvd · haproxy · debian · 13
3.0.11-1+deb13u4· all · trixie-securityAffected
nvd · haproxy · debian · 13
- [vim-haproxy]Affected
Source package: [haproxy]
Details (5)
3.0.11-1+deb13u3· all · trixieAffected
nvd · haproxy · debian · 13
3.0.11-1+deb13u3· all · trixieAffected
nvd · haproxy · debian · 13
3.0.11-1+deb13u3· all · trixie-security · Historical versionAffected
nvd · haproxy · debian · 13
3.0.11-1+deb13u3· all · trixie-securityAffected
nvd · haproxy · debian · 13
3.0.11-1+deb13u4· all · trixie-securityAffected
nvd · haproxy · debian · 13
Observed:
References
- [https://ftp.suse.com/pub/projects/security/csaf/suse-su-2026_22663-1.json]
- [https://github.com/haproxy/haproxy/commit/9a6d1fe3f00d86ab4ea6ea6ea0a5d48fc058a513]
- [https://nvd.nist.gov/vuln/detail/CVE-2026-55204]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2026-55204]
- [https://osv.dev/vulnerability/UBUNTU-CVE-2026-55204]
- [https://security-tracker.debian.org/tracker/CVE-2026-55204]
- [https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-55204.json]
- [https://ubuntu.com/security/notices/USN-8459-1]
- [https://wid.cert-bund.de/.well-known/csaf/white/2026/wid-sec-w-2026-2012.json]
- [https://www.vulncheck.com/advisories/haproxy-null-pointer-dereference-in-hpack-dht-insert-function]
[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX] · [Ubuntu Security Notices (USN)]