5.8

CVE-2026-33555: haproxy

Modified
AliasesMGASA-2026-0146SUSE-SU-2026:1568-1SUSE-SU-2026:21280-1
Published 13-04-2026Last modified 18-10-2026

Vulnerability summary

CVE-2026-33555 is a medium (CVSS 5.8) vulnerability in haproxy. EPSS estimates a 0.60% chance of exploitation in the next 30 days, higher than 48.2% of scored vulnerabilities. 1 public exploit is recorded.

Overall risk
33/100
0100
Medium · default modelHow is this calculated?
CVSS score
5.8/10
010
Medium · v3.1 (NVD)
EPSS score
0.60%
0%100%
Low · +0.31 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits1reference

Advisory lineage

Upstream 0 · Downstream 0 · Related 2
CGA-FRCQ-Q396-93FJUSN-8208-1

Timeline

  1. 13-04-2026
    PublishedVulnerability first disclosed.
  2. 18-10-2026
    Last modifiedVulnerability information updated.

Description

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.

CVSS metrics

7 scores · 7 sources · 1 version

EPSS trend

Probability

0.60%

Chance of exploitation in the next 30 days

Percentile

48%

Versus all other CVEs

30-day change

Increase +0.31 pp

From 0.30% on 22-09-2026

22-09-202622-10-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

1 found
  • referenceUnverified

    Exploit Reference (r3verii.github.io)

    Maturity: unknown

Weaknesses

CWE · root cause

Affected systems

Chainguard5 products
  • haproxy-2.6< 2.6.31-r0
  • haproxy-2.8< 2.8.26-r0
  • haproxy-3.0< 3.0.19-r0
  • haproxy-3.1All versions (No fix recorded)
  • haproxy-3.2< 3.2.15-r0
Suse3 products
  • haproxy&distro=SUSE Linux Enterprise High Availability Extension 15 SP6< 2.8.11+git0.01c1056a4-150600.3.12.1
  • haproxy&distro=SUSE Linux Enterprise High Availability Extension 15 SP7< 2.8.11+git0.01c1056a4-150600.3.12.1
  • haproxy&distro=SUSE Linux Micro 6.2< 3.2.15+git64.0fc44b458-160000.2.1
Opensuse2 products
  • haproxy&distro=openSUSE Leap 16.0< 3.2.15+git64.0fc44b458-160000.2.1
  • haproxy&distro=openSUSE Tumbleweed< 3.3.6+git91.af5637e93-1.1
Debian1 product
  • haproxyAll versions (No fix recorded) | < 2.6.12-1+deb12u4 | < 3.0.11-1+deb13u3 | < 3.2.15-1
Haproxy1 product
  • haproxy≥ 2.6, < 3.3.6 | ≥ 2.6.0, < 3.3.6
Mageia1 product
  • haproxy< 2.8.18-1.1.mga9
Redhat1 product
  • haproxy< 0:3.0.19-1.1.hum1
Ubuntu1 product
  • haproxy< 2.8.16-0ubuntu0.24.04.2 | < 3.0.12-0ubuntu0.25.10.4 | < 3.2.9-1ubuntu2.1
Wolfi1 product
  • haproxy-3.2< 3.2.15-r0

9 vendors · 16 products

References

26 links
Show all 26 references