VulnerabilityPublished 23 Oct 2026Updated 27 Oct 2026

CVE-2026-110353: (HAProxy 3.2 before 3.4.6 allows a remote unauthenticated attacker to c ...)

Affects haproxySource GCVE Database

Authoritative record:CVE-2026-110353· High 7.5

Not known to be exploited · CVSS 7.5 High · fixed in 3.4.6 : patch haproxy soon.

Data as of 27 Oct 2026, 08:12 UTC

CVSS 3.1 base score

7.5High

How severe the flaw is on the 0–10 CVSS scale.

Patch: Available – fixed in 3.4.6

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 22 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Ubuntu 26.10haproxy`pkg:deb/ubuntu/haproxy?arch=source&distro=stonking`Other threats	Affected 3.2.9-1ubuntu2 – 3.4.2-1ubuntu4 6 affected builds	Fixed in–
Ubuntu 26.04 LTShaproxy`pkg:deb/ubuntu/haproxy?arch=source&distro=resolute`Other threats	Affected 3.0.10-1ubuntu3 – 3.2.25-0ubuntu0.26.04.1 6 affected builds	Fixed in–
Ubuntu 24.04 LTShaproxy`pkg:deb/ubuntu/haproxy?arch=source&distro=noble`Other threats	Affected 2.6.15-1ubuntu2 – 2.8.30-0ubuntu0.24.04.1 13 affected builds	Fixed in–
Ubuntu 22.04 LTShaproxy`pkg:deb/ubuntu/haproxy?arch=source&distro=jammy`Other threats	Affected 2.2.9-2ubuntu2 – 2.4.30-0ubuntu0.22.04.2 21 affected builds	Fixed in–
Ubuntu 20.04 LTShaproxy`pkg:deb/ubuntu/haproxy?arch=source&distro=focal`Other threats	Affected 2.0.5-1 – 2.0.33-0ubuntu0.1 20 affected builds	Fixed in–
Ubuntu Pro 18.04 LTShaproxy`pkg:deb/ubuntu/haproxy?arch=source&distro=esm-infra/bionic`Other threats	Affected 1.7.9-1ubuntu1 – 1.8.8-1ubuntu0.13+esm3 18 affected builds	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Upgrade HAProxy to version 3.4.6 or later where this vulnerability is fixed. Since this is a high severity denial of service vulnerability, applying the official fix is recommended to prevent service disruption.

Description

HAProxy versions 3.2 before 3.4.6 contain a vulnerability that allows a remote unauthenticated attacker to cause a denial of service (DoS) condition. This flaw does not impact confidentiality or integrity but can disrupt availability by crashing or otherwise incapacitating the service.

Impact

The vulnerability allows remote unauthenticated attackers to cause a denial of service, potentially disrupting service availability. There is no impact on confidentiality or integrity according to the CVSS vector.

Summary

CVE-2026-110353 affects HAProxy versions 3.2 up to but not including 3.4.6. It permits a remote attacker with no authentication to trigger a denial of service, impacting the availability of the HAProxy service. The vulnerability has a CVSS 3.1 base score of 7.5, reflecting high severity due to the ease of exploitation (network vector, low attack complexity, no privileges or user interaction required) and the impact on availability only. No known exploits in the wild have been reported. The issue is fixed in HAProxy version 3.4.6.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 27 Oct 2026, 08:12 UTC

Technical details

References

Community reviews

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