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TI-2026-79141 Aliases CVE-2026-110354GHSA-vqpp-w68q-p3f5

Persistent CPU exhaustion in HAProxy via chunked HTTP requests

Priority MEDIUM 40CWE-835Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Partial Red Hat: 1 fixed, 6 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-835.

Summary

HAProxy 3.0.0 before 3.0.30, 3.2.0 before 3.2.26, 3.3.0 before 3.3.17, 3.4.0 before 3.4.6 and 3.5-dev before 3.5-dev9 are affected. The HTTP/1.1 parser repeatedly reprocesses the same bytes of a chunked request without making progress (CWE-835). A remote unauthenticated attacker can send such requests to keep worker threads at 100% CPU after timeouts and client disconnects, until the process is restarted.

Written with Claude Haiku 5.5 from the sources below · 2026-11-05

Description from the CNA

HAProxy 3 before 3.4.6 allows a remote unauthenticated attacker to cause a denial of service (persistent worker-thread CPU exhaustion) via an HTTP/1.1 chunked request. Although the H1 multiplexer drains the request before closing the stream, the parser repeatedly re-processes the same bytes without making progress. The affected thread stays busy at 100% CPU after timeouts expire and after the client disconnects, and repeated requests can consume all worker threads until the process is restarted.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00807 57th percentileScored 2026-11-07
Fix Partial HAProxy (HAProxy): 3.0.30, 3.2.26, 3.3.17 +2HAProxy Enterprise Edition (HAProxy): 3.0r1-362.1441, 3.2r1-378.1259, 3.3r1-377.1005+2 more productsRed Hat: 1 advisoryRed Hat: 1 fixed, 6 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
HAProxyHAProxy3.0.0 to before 3.0.30; 3.2.0 to before 3.2.26; 3.3.0 to before 3.3.17; 3.4.0 to before 3.4.6; 3.5-dev to before 3.5-dev93.0.30, 3.2.26, 3.3.17, 3.4.6, 3.5-dev9Patch availableCNA
HAProxyHAProxy Enterprise Edition3.0r1 to before 3.0r1-362.1441; 3.2r1 to before 3.2r1-378.1259; 3.3r1 to before 3.3r1-377.10053.0r1-362.1441, 3.2r1-378.1259, 3.3r1-377.1005Patch availableCNA
HAProxy TechnologiesHAProxy Kubernetes Ingress Controller3.2.0 to before 3.2.173.2.17Patch availableCNA
HAProxy TechnologiesKubernetes Ingress Controller Enterprise3.2.0 to before 3.2.17-ee1; 3.0 to before 3.0.16-ee17; 1.11 to before 1.11.14-ee113.2.17-ee1, 3.0.16-ee17, 1.11.14-ee11Patch availableCNA
  • HAProxy VendorHAProxy Affected 3.0.0 to before 3.0.30; 3.2.0 to before 3.2.26; 3.3.0 to before 3.3.17; 3.4.0 to before 3.4.6; 3.5-dev to before 3.5-dev9 Fixed in 3.0.30, 3.2.26, 3.3.17, 3.4.6, 3.5-dev9 Patch available CNA
  • HAProxy Enterprise Edition VendorHAProxy Affected 3.0r1 to before 3.0r1-362.1441; 3.2r1 to before 3.2r1-378.1259; 3.3r1 to before 3.3r1-377.1005 Fixed in 3.0r1-362.1441, 3.2r1-378.1259, 3.3r1-377.1005 Patch available CNA
  • HAProxy Kubernetes Ingress Controller VendorHAProxy Technologies Affected 3.2.0 to before 3.2.17 Fixed in 3.2.17 Patch available CNA
  • Kubernetes Ingress Controller Enterprise VendorHAProxy Technologies Affected 3.2.0 to before 3.2.17-ee1; 3.0 to before 3.0.16-ee17; 1.11 to before 1.11.14-ee11 Fixed in 3.2.17-ee1, 3.0.16-ee17, 1.11.14-ee11 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:haproxy:haproxy:*:*:*:*:*:*:*:*——HAProxy
  • cpe:2.3:a:haproxy:haproxy:*:*:*:*:*:*:*:* Versions — — ·HAProxy

Remediation

Upgrade HAProxy to 3.0.30, 3.2.26, 3.3.17, 3.4.6 or 3.5-dev9, HAProxy Enterprise Edition to 3.0r1-362.1441, 3.2r1-378.1259 or 3.3r1-377.1005, HAProxy Kubernetes Ingress Controller to 3.2.17, and Kubernetes Ingress Controller Enterprise to 3.2.17-ee1, 3.0.16-ee17 or 1.11.14-ee11. Red Hat Hardened Images is fixed by RHSA-2026:83844. Red Hat's plan for Red Hat Enterprise Linux 7, 8 and 9, Red Hat Ceph Storage 5 and Red Hat OpenShift Container Platform 4 and 5 is none available.

Written with Claude Haiku 5.5 from the sources below · 2026-11-05

  • Fix · CNA HAProxy (HAProxy) Fixed in 3.0.30, 3.2.26, 3.3.17, 3.4.6, 3.5-dev9
  • Fix · CNA HAProxy Enterprise Edition (HAProxy) Fixed in 3.0r1-362.1441, 3.2r1-378.1259, 3.3r1-377.1005
  • Fix · CNA HAProxy Kubernetes Ingress Controller (HAProxy Technologies) Fixed in 3.2.17
  • Fix · CNA Kubernetes Ingress Controller Enterprise (HAProxy Technologies) Fixed in 3.2.17-ee1, 3.0.16-ee17, 1.11.14-ee11

Red Hat 1 advisory

  • RHSA-2026:83844 Released 2026-10-16 · Red Hat rating Important
    Red Hat Hardened Images RPMs bug fix and enhancement update
    • Red Hat Hardened Images haproxy-3.0.30-0.1.hum1@aarch64, haproxy-3.0.30-0.1.hum1@s390x, haproxy-3.0.30-0.1.hum1@src +1

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Ceph Storage 5AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 7AffectedNo fix yet
Red Hat Enterprise Linux 8AffectedNo fix yet
Red Hat Enterprise Linux 9AffectedNo fix yet
Red Hat OpenShift Container Platform 4AffectedNo fix yet
Red Hat OpenShift Container Platform 5AffectedNo fix yet
Red Hat Hardened ImagesFixed RHSA-2026:83844
Not affected: 1 product
  • Red Hat Enterprise Linux 10

Timeline

  1. 2026-10-22 Threatist record created from CVE-2026-110354
  2. 2026-10-22 Alias added: GHSA-vqpp-w68q-p3f5
  3. 2026-10-22 CISA SSVC decision points changed
  4. 2026-10-22 Priority changed: MEDIUM → LOW
  5. 2026-10-23 Affected versions changed · Red Hat
  6. 2026-10-23 CVSS score added · Red Hat
  7. 2026-10-23 Priority changed: LOW → MEDIUM
  8. 2026-10-29 Fix available: RHSA-2026:83844 · Red Hat
  9. 2026-10-29 Fix available: Red Hat Hardened Images · Red Hat
  10. 2026-10-30 Affected versions changed · Red Hat
  11. 2026-11-05 Affected versions changed · Red Hat

References

Advisory 1

  • TI-2020-08973 In hpack_dht_insert in hpack-tbl.c in the HPACK decoder in HAProxy 1.8 through 2.x before… CVSS 3.1HIGH 8.8
  • TI-2023-21094 HAProxy through 2.0.32, 2.1.x and 2.2.x through 2.2.30, 2.3.x and 2.4.x through 2.4.23… CVSS 3.1HIGH 7.2
  • TI-2019-10602 HAProxy through 2.0.2 allows attackers to cause a denial of service (ha_panic) via… CVSS 3.0HIGH 7.5
  • TI-2021-17418 An integer overflow exists in HAProxy 2.0 through 2.5 in htx_add_header that can be… CVSS 3.1HIGH 7.5
  • TI-2016-04651 HAproxy 1.6.x before 1.6.6, when a deny comes from a reqdeny rule, allows remote… CVSS 3.0HIGH 7.5
  • TI-2026-25946 An issue was discovered in HAProxy before 3.3.6. CVSS 3.1MEDIUM 5.8
See all 42 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences