{"id":"UBUNTU-CVE-2026-55204","details":"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.","modified":"2026-06-24T11:02:00.607443075Z","published":"2026-06-19T00:00:00Z","related":["USN-8459-1"],"upstream":["CVE-2026-55204"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-55204"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-55204"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-8459-1"}],"affected":[{"package":{"name":"haproxy","ecosystem":"Ubuntu:Pro:16.04:LTS","purl":"pkg:deb/ubuntu/haproxy?arch=source&distro=esm-infra%2Fxenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.5.14-1","1.5.15-1","1.6.2-1","1.6.2-2","1.6.2-2ubuntu1","1.6.2-2ubuntu3","1.6.3-1","1.6.3-1ubuntu0.1","1.6.3-1ubuntu0.2","1.6.3-1ubuntu0.3","1.6.3-1ubuntu0.3+esm1","1.6.3-1ubuntu0.3+esm2"],"ecosystem_specific":{"binaries":[{"binary_name":"haproxy","binary_version":"1.6.3-1ubuntu0.3+esm2"},{"binary_name":"vim-haproxy","binary_version":"1.6.3-1ubuntu0.3+esm2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-55204.json"}},{"package":{"name":"haproxy","ecosystem":"Ubuntu:Pro:18.04:LTS","purl":"pkg:deb/ubuntu/haproxy?arch=source&distro=esm-infra%2Fbionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.7.9-1ubuntu1","1.7.9-1ubuntu2","1.8.4-1","1.8.7-1","1.8.8-1","1.8.8-1ubuntu0.1","1.8.8-1ubuntu0.2","1.8.8-1ubuntu0.3","1.8.8-1ubuntu0.4","1.8.8-1ubuntu0.6","1.8.8-1ubuntu0.7","1.8.8-1ubuntu0.8","1.8.8-1ubuntu0.9","1.8.8-1ubuntu0.10","1.8.8-1ubuntu0.11","1.8.8-1ubuntu0.13","1.8.8-1ubuntu0.13+esm2","1.8.8-1ubuntu0.13+esm3"],"ecosystem_specific":{"binaries":[{"binary_version":"1.8.8-1ubuntu0.13+esm3","binary_name":"haproxy"},{"binary_name":"vim-haproxy","binary_version":"1.8.8-1ubuntu0.13+esm3"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-55204.json"}},{"package":{"name":"haproxy","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/haproxy?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.0.5-1","2.0.8-1","2.0.9-1","2.0.10-1","2.0.10-1ubuntu1","2.0.11-1ubuntu1","2.0.12-1ubuntu2","2.0.13-1ubuntu2","2.0.13-2","2.0.13-2ubuntu0.1","2.0.13-2ubuntu0.2","2.0.13-2ubuntu0.3","2.0.13-2ubuntu0.5","2.0.29-0ubuntu1","2.0.29-0ubuntu1.1","2.0.29-0ubuntu1.3","2.0.31-0ubuntu0.1","2.0.31-0ubuntu0.2","2.0.31-0ubuntu0.3","2.0.33-0ubuntu0.1"],"ecosystem_specific":{"binaries":[{"binary_name":"haproxy","binary_version":"2.0.33-0ubuntu0.1"},{"binary_name":"vim-haproxy","binary_version":"2.0.33-0ubuntu0.1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-55204.json"}},{"package":{"name":"haproxy","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/haproxy?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.4.30-0ubuntu0.22.04.2"}]}],"versions":["2.2.9-2ubuntu2","2.4.8-1","2.4.8-2ubuntu3","2.4.11-1ubuntu1","2.4.12-1ubuntu1","2.4.12-1ubuntu2","2.4.13-1ubuntu1","2.4.14-1ubuntu1","2.4.18-0ubuntu1","2.4.18-0ubuntu1.1","2.4.18-0ubuntu1.2","2.4.18-0ubuntu1.3","2.4.22-0ubuntu0.22.04.1","2.4.22-0ubuntu0.22.04.2","2.4.22-0ubuntu0.22.04.3","2.4.24-0ubuntu0.22.04.1","2.4.24-0ubuntu0.22.04.2","2.4.24-0ubuntu0.22.04.3","2.4.29-0ubuntu0.22.04.1","2.4.30-0ubuntu0.22.04.1"],"ecosystem_specific":{"binaries":[{"binary_name":"haproxy","binary_version":"2.4.30-0ubuntu0.22.04.2"},{"binary_name":"vim-haproxy","binary_version":"2.4.30-0ubuntu0.22.04.2"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-55204.json"}},{"package":{"name":"haproxy","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/haproxy?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.8.16-0ubuntu0.24.04.3"}]}],"versions":["2.6.15-1ubuntu2","2.8.5-1ubuntu1","2.8.5-1ubuntu2","2.8.5-1ubuntu3","2.8.5-1ubuntu3.1","2.8.5-1ubuntu3.2","2.8.5-1ubuntu3.3","2.8.5-1ubuntu3.4","2.8.15-0ubuntu0.24.04.1","2.8.16-0ubuntu0.24.04.1","2.8.16-0ubuntu0.24.04.2"],"ecosystem_specific":{"binaries":[{"binary_version":"2.8.16-0ubuntu0.24.04.3","binary_name":"haproxy"},{"binary_version":"2.8.16-0ubuntu0.24.04.3","binary_name":"vim-haproxy"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-55204.json"}},{"package":{"name":"haproxy","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/haproxy?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.0.12-0ubuntu0.25.10.5"}]}],"versions":["3.0.8-1ubuntu1","3.0.8-1ubuntu1.1","3.0.10-1ubuntu1","3.0.10-1ubuntu2","3.0.10-1ubuntu3","3.0.12-0ubuntu0.25.10.1","3.0.12-0ubuntu0.25.10.3","3.0.12-0ubuntu0.25.10.4"],"ecosystem_specific":{"binaries":[{"binary_name":"haproxy","binary_version":"3.0.12-0ubuntu0.25.10.5"},{"binary_version":"3.0.12-0ubuntu0.25.10.5","binary_name":"vim-haproxy"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-55204.json"}},{"package":{"name":"haproxy","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/haproxy?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.2.9-1ubuntu2.2"}]}],"versions":["3.0.10-1ubuntu3","3.2.9-1ubuntu1","3.2.9-1ubuntu2","3.2.9-1ubuntu2.1"],"ecosystem_specific":{"availability":"No subscription required","binaries":[{"binary_version":"3.2.9-1ubuntu2.2","binary_name":"haproxy"},{"binary_version":"3.2.9-1ubuntu2.2","binary_name":"vim-haproxy"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-55204.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},{"type":"CVSS_V4","score":"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"},{"type":"Ubuntu","score":"medium"}]}