CVE-2026-55204
highpriority · track · 0EPSS 0.005 · 41 %ileDEEURUUSEPSS · scored 2026-10-24
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.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.6–8.7
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (61)
Products and version ranges known to be affected.
advisories (2)
Vendor and ecosystem advisories describing this.
- WID-SEC-W-2026-2012HAProxy: Mehrere SchwachstellenDeutsch2026-06-18csaf · cert_bundDE
Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in HAProxy ausnutzen, um Dateien zu manipulieren oder einen Denial of Service zu verursachen.
- BIT-haproxy-2026-55204HAProxy - NULL Pointer Dereference in hpack_dht_insert Function2026-06-29vendor · osvUS
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.
also known as (5)
Other names and identifiers for this entity.
sources
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references (7)
External citations — patches, advisories, analysis.
- https://github.com/haproxy/haproxyPatchcnnvd
- https://github.com/haproxy/haproxy/commit/9a6d1fe3f00d86ab4ea6ea6ea0a5d48fc058a513cnnvd
- https://www.vulncheck.com/advisories/haproxy-null-pointer-dereference-in-hpack-dht-insert-functioncnnvd
- https://github.com/haproxy/haproxy/commit/9a6d1fe3f00d86ab4ea6ea6ea0a5d48fc058a513enisa_euvd
- https://www.vulncheck.com/advisories/haproxy-null-pointer-dereference-in-hpack-dht-insert-functionenisa_euvd
- https://github.com/haproxy/haproxy/commit/9a6d1fe3f00d86ab4ea6ea6ea0a5d48fc058a513Patchnvd
- https://www.vulncheck.com/advisories/haproxy-null-pointer-dereference-in-hpack-dht-insert-functionThird Party Advisorynvd
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