CVE-2026-33555 (GCVE-0-2026-33555)

Vulnerability from cvelistv5 – Published: 2026-04-13 00:00 – Updated: 2026-10-18 20:07
VLAI
Summary
An issue was discovered in HAProxy before 3.3.6. The HTTP/3 parser does not check that the received body length matches a previously announced content-length when the stream is closed via a frame with an empty payload. This can cause desynchronization issues with the backend server and could be used for request smuggling. The earliest affected version is 2.6.
Severity
4 (Medium)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N
SSVC
Exploitation: poc Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-04-22 18:42 UTC
CWE
  • CWE-130 - Improper Handling of Length Parameter Inconsistency
Assigner
mitre CNA under the mitre root
CNA scorecard E 29/100 over 2359 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
HAProxy HAProxy Affected: 2.6 , < 3.3.6 (custom)
    cpe:2.3:a:haproxy:haproxy:*:*:*:*:*:*:*:*
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