CVE Intelligence
High

CVE-2025-11230 — Denial of service vulnerability in HAProxy mjson library

Inefficient algorithm complexity in mjson in HAProxy allows remote attackers to cause a denial of service via specially crafted JSON requests.

Published Nov 19, 2025 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: canonical

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 0.7% (30-day exploitation probability)+8
  • Technical severity (high)+6
  • Automatable exploitation (SSVC)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
0.69%
ahead of 52% of scored CVEs · Oct 15, 2026
Affects
Haproxy
Aloha Appliance and 4 more
CVSS base
7.5
High · 2 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
None
none · proof-of-concept · active
Automatable
Yes
can an attacker script the kill-chain steps
Technical impact
Partial
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Haproxy Aloha Appliance, Haproxy Haproxy, Haproxy Haproxy Enterprise…).
  2. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
  3. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  4. Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Haproxy Aloha Appliance ≥ 14.5.0 and < 14.5.33≥ 15.5.0 and < 15.5.28≥ 16.5.0 and < 16.5.19≥ 17.0.0 and < 17.0.7 Vulnerable NIST National Vulnerability Database
Haproxy Haproxy ≥ 2.4.0 and < 2.4.30≥ 2.6.0 and < 2.6.23≥ 2.8.0 and < 2.8.16≥ 3.0.0 and < 3.0.12≥ 3.1.0 and < 3.1.9≥ 3.2.0 and < 3.2.6 Vulnerable NIST National Vulnerability Database
Haproxy Haproxy Enterprise version 2.4r1-1.0.0-253.271version 2.4r1-1.0.0-254.271version 2.4r1-1.0.0-259.342version 2.4r1-1.0.0-263.343version 2.4r1-1.0.0-264.356version 2.4r1-1.0.0-268.356version 2.4r1-1.0.0-268.373version 2.4r1-1.0.0-268.459
and 178 more version 2.4r1-1.0.0-268.464version 2.4r1-1.0.0-268.477version 2.4r1-1.0.0-268.499version 2.4r1-1.0.0-268.553version 2.4r1-1.0.0-268.560version 2.4r1-1.0.0-268.564version 2.4r1-1.0.0-268.596version 2.4r1-1.0.0-269.596version 2.4r1-1.0.0-269.599version 2.4r1-1.0.0-270.616version 2.4r1-1.0.0-271.673version 2.4r1-1.0.0-271.677version 2.4r1-1.0.0-272.683version 2.4r1-1.0.0-272.686version 2.4r1-1.0.0-272.728version 2.4r1-1.0.0-274.752version 2.4r1-1.0.0-276.752version 2.4r1-1.0.0-277.814version 2.4r1-1.0.0-277.831version 2.4r1-1.0.0-278.838version 2.4r1-1.0.0-279.852version 2.4r1-1.0.0-279.859version 2.4r1-1.0.0-279.877version 2.4r1-1.0.0-279.911version 2.4r1-1.0.0-279.940version 2.4r1-1.0.0-279.952version 2.4r1-1.0.0-279.953version 2.4r1-1.0.0-279.956version 2.4r1-1.0.0-280.956version 2.4r1-1.0.0-282.998version 2.4r1-1.0.0-282.999version 2.4r1-1.0.0-284.999version 2.4r1-1.0.0-285.1010version 2.4r1-1.0.0-286.1064version 2.4r1-1.0.0-286.1068version 2.4r1-1.0.0-286.1089version 2.4r1-1.0.0-286.1094version 2.4r1-1.0.0-288.1094version 2.4r1-1.0.0-288.1158version 2.4r1-1.0.0-288.1167version 2.4r1-1.0.0-288.1189version 2.4r1-1.0.0-289.1189version 2.4r1-1.0.0-290.1239version 2.4r1-1.0.0-291.1246version 2.4r1-1.0.0-292.1293version 2.4r1-1.0.0-294.1346version 2.4r1-1.0.0-294.1364version 2.4r1-1.0.0-294.1376version 2.4r1-1.0.0-294.1377version 2.4r1-1.0.0-294.1442version 2.6r1-1.0.0-281.466version 2.6r1-1.0.0-282.561version 2.6r1-1.0.0-283.562version 2.6r1-1.0.0-283.565version 2.6r1-1.0.0-283.616version 2.6r1-1.0.0-283.632version 2.6r1-1.0.0-283.633version 2.6r1-1.0.0-283.636version 2.6r1-1.0.0-284.636version 2.6r1-1.0.0-285.726version 2.6r1-1.0.0-285.727version 2.6r1-1.0.0-287.727version 2.6r1-1.0.0-288.770version 2.6r1-1.0.0-288.773version 2.6r1-1.0.0-288.848version 2.6r1-1.0.0-288.849version 2.6r1-1.0.0-289.1020version 2.6r1-1.0.0-289.1028version 2.6r1-1.0.0-289.1041version 2.6r1-1.0.0-289.873version 2.6r1-1.0.0-289.975version 2.6r1-1.0.0-289.976version 2.6r1-1.0.0-291.1046version 2.6r1-1.0.0-292.1046version 2.6r1-1.0.0-292.1055version 2.6r1-1.0.0-292.1120version 2.6r1-1.0.0-292.1147version 2.6r1-1.0.0-292.1148version 2.6r1-1.0.0-292.1156version 2.6r1-1.0.0-292.1181version 2.6r1-1.0.0-292.1187version 2.6r1-1.0.0-293.1189version 2.6r1-1.0.0-293.1190version 2.6r1-1.0.0-294.1212version 2.6r1-1.0.0-294.1285version 2.6r1-1.0.0-295.1303version 2.6r1-1.0.0-296.1392version 2.6r1-1.0.0-296.1416version 2.6r1-1.0.0-299.1416version 2.6r1-1.0.0-299.1474version 2.6r1-1.0.0-299.1487version 2.6r1-1.0.0-299.1511version 2.6r1-1.0.0-299.1542version 2.6r1-1.0.0-299.1557version 2.6r1-1.0.0-299.1596version 2.6r1-1.0.0-299.1603version 2.6r1-1.0.0-299.1606version 2.6r1-1.0.0-299.1618version 3.0r1-1.0.0-339.395version 3.0r1-1.0.0-344.503version 3.0r1-1.0.0-344.495version 3.0r1-1.0.0-342.482version 3.0r1-1.0.0-341.475version 3.0r1-1.0.0-339.471version 3.0r1-1.0.0-339.466version 3.0r1-1.0.0-339.455version 3.0r1-1.0.0-339.415version 3.0r1-1.0.0-339.405version 3.0r1-1.0.0-344.561version 3.0r1-1.0.0-337.394version 3.0r1-1.0.0-337.390version 3.0r1-1.0.0-337.363version 2.8r1-1.0.0-326.1073version 2.8r1-1.0.0-324.947version 2.8r1-1.0.0-324.1072version 2.8r1-1.0.0-324.1071version 2.8r1-1.0.0-324.1030version 2.8r1-1.0.0-322.942version 3.1r1-1.0.0-346.274version 3.1r1-1.0.0-348.519version 3.1r1-1.0.0-347.449version 3.1r1-1.0.0-347.431version 3.1r1-1.0.0-347.419version 3.1r1-1.0.0-347.405version 3.1r1-1.0.0-347.362version 3.1r1-1.0.0-347.338version 3.1r1-1.0.0-347.299version 3.1r1-1.0.0-346.287version 2.6r1-1.0.0-301.1666version 3.1r1-1.0.0-345.233version 3.0r1-1.0.0-346.792version 3.0r1-1.0.0-345.673version 3.0r1-1.0.0-344.672version 3.0r1-1.0.0-344.655version 3.0r1-1.0.0-344.641version 3.0r1-1.0.0-344.608version 3.0r1-1.0.0-344.591version 3.0r1-1.0.0-344.564version 2.8r1-1.0.0-310.364version 2.8r1-1.0.0-312.592version 2.8r1-1.0.0-311.453version 2.8r1-1.0.0-311.452version 2.8r1-1.0.0-311.449version 2.8r1-1.0.0-310.424version 2.8r1-1.0.0-310.422version 2.8r1-1.0.0-310.418version 2.8r1-1.0.0-310.374version 2.8r1-1.0.0-310.373version 2.8r1-1.0.0-321.934version 2.8r1-1.0.0-310.350version 2.8r1-1.0.0-307.317version 2.8r1-1.0.0-306.289version 2.8r1-1.0.0-306.288version 2.8r1-1.0.0-305.285version 2.8r1-1.0.0-305.279version 2.8r1-1.0.0-304.266version 2.8r1-1.0.0-302.234version 2.6r1-1.0.0-300.1666version 2.8r1-1.0.0-317.613version 2.8r1-1.0.0-321.937version 2.8r1-1.0.0-321.931version 2.8r1-1.0.0-321.919version 2.8r1-1.0.0-321.901version 2.8r1-1.0.0-321.895version 2.8r1-1.0.0-320.895version 2.8r1-1.0.0-320.853version 2.8r1-1.0.0-320.851version 2.8r1-1.0.0-320.831version 2.8r1-1.0.0-320.781version 2.8r1-1.0.0-320.780version 2.8r1-1.0.0-320.770version 2.8r1-1.0.0-320.761version 2.8r1-1.0.0-320.750version 2.8r1-1.0.0-319.723version 2.8r1-1.0.0-319.699version 2.8r1-1.0.0-318.674version 2.8r1-1.0.0-312.613version 2.8r1-1.0.0-320.783
Vulnerable NIST National Vulnerability Database
Haproxy Kubernetes Ingress Controller < 1.9.14-ee7≥ 3.0.0-ee1 and < 3.0.15-ee4≥ 1.10.10-ee1 and < 1.11.12-ee10< 3.1.12 Vulnerable NIST National Vulnerability Database
HAProxy Technologies HAProxy Community Edition ≥ 2.4.0 and < 2.4.30≥ 2.6.0 and < 2.6.23≥ 2.8.0 and < 2.8.16≥ 3.0.0 and < 3.0.12≥ 3.1.0 and < 3.1.9≥ 3.2.0 and < 3.2.6 Vulnerable CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
7.5 CVSS 3.1 High 3.9 3.6 security@ubuntu.com via NIST National Vulnerability Database
7.5 CVSS 3.1 High — — canonical via CVE Program (cve.org) e CISA ADP
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (score shown at the top: security@ubuntu.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-407

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 15, 2026 · 3 reading(s) · max 0.69%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
web/proxy/WAF logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first.

  • 2026
  • Affected products added · haproxy technologies/haproxy community edition
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • SSVC assessment updated
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 13, 2026
  • CVSS changed · 7.5
    Oct 13, 2026 · NIST National Vulnerability Database
  • Source status changed · → Analyzed
    Oct 13, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 13, 2026 · NIST National Vulnerability Database
  • 2025
  • CVE published
    Nov 19, 2025 · canonical

Source activity

Repeated readings are counted rather than listed.

  • 1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

1 on the record

Elsewhere on this site

Haproxy
every CVE for this vendor
CWE-407
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-90678 An issue was discovered in HAProxy 3.3.0 through 3.4.4 and in 3.5-dev1 through 3.5-dev5… Sep 13, 2026
  • CVE-2026-26080 Unchecked Return Value in Haproxy Jul 20, 2026
  • CVE-2026-26081 HAProxy Community Edition 3.0 through 3.3 before 3.3.3 lacks a length check for the… Jul 20, 2026
  • CVE-2026-55203 HAProxy - Integer Overflow in FCGI Demux Record Length Field Jun 18, 2026
  • CVE-2026-55204 HAProxy - NULL Pointer Dereference in hpack_dht_insert Function Jun 18, 2026
  • CVE-2026-33555 An issue was discovered in HAProxy before 3.3.6. The HTTP/3 parser does not check that… Apr 13, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No fixed version, patch or mitigation documented.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2025-11230 is "Denial of service vulnerability in HAProxy mjson library", rated High. It affects Aloha Appliance (Haproxy); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.5 describes technical severity. EPSS 0.69% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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