VulnerabilityPublished 18 Sep 2026Updated 6 Nov 2026

CVE-2026-93564: HAProxy PROXY-v2 nested-TLV grandchild ByteBuf reference-count leak (incomplete fix of PR #16881)

Source GCVE Database

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Authoritative record:CVE-2026-93564· High 7.5

Not known to be exploited · CVSS 7.5 High : patch Red Hat Build of Apache Camel 3.33.3.SP2 soon.

Data as of 6 Nov 2026, 13:49 UTC

CVSS 3.1 base score

7.5High

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

Thin evidence

One scorer or none

CVSS scores by source
CNA (redhat)	CVSS 3.1	7.5

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 18 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 6 Nov 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.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), 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.

ghsa-74qm-9qc5-ff4g

What to do

Patches and advisories

Affected software

Product	Affected	Fixed in
Red Hat Build of Apache Camel 3.33.3.SP2io.netty/netty-codec-haproxy	Affected–	Fixed in–
Red Hat Build of Debezium 3.6netty-codec-haproxy	Affected–	Fixed in–
Red Hat build of Keycloak 26.4keycloak-rhel9-container	Affected–	Fixed in–
Red Hat build of Keycloak 26.4keycloak-rhel9-operator-bundle-container	Affected–	Fixed in–
Red Hat build of Keycloak 26.4keycloak-rhel9-operator-container	Affected–	Fixed in–
Red Hat build of Keycloak 26.6.8netty-codec-haproxy	Affected–	Fixed in–

AI-suggested

A security update is available as part of Red Hat build of Quarkus 3.33.3.SP2, which includes a fix for this vulnerability. Users should apply this update to remediate the issue. Since the vulnerability is not in a cloud service, manual patching is required. No additional mitigation steps are indicated in the advisory.

Description

CVE-2026-93564 is a vulnerability in HAProxy's PROXY-v2 protocol handling where an incomplete fix for a previous issue leads to a ByteBuf reference-count leak in nested TLV grandchild structures. This flaw can cause a denial of service due to resource exhaustion. The vulnerability has a high severity rating with a CVSS score of 7.5. A Red Hat advisory references this issue in the context of their Quarkus build, indicating that security updates are available.

Impact

The vulnerability results in a denial of service (DoS) condition caused by a memory leak in HAProxy's PROXY-v2 nested TLV handling. There is no reported impact on confidentiality or integrity. Exploitation does not require privileges or user interaction and can be performed remotely over the network.

Summary

The vulnerability identified as CVE-2026-93564 affects HAProxy's PROXY-v2 nested TLV processing, specifically causing a ByteBuf reference-count leak due to an incomplete fix of a prior pull request (#16881). This leak can lead to denial of service conditions by exhausting memory resources. The issue has been assigned a CVSS 3.1 base score of 7.5, indicating high severity with network attack vector, low attack complexity, no privileges required, no user interaction, and impact limited to availability. The Red Hat advisory for Quarkus 3.33.3.SP2 mentions security updates addressing this and other vulnerabilities, implying that a fix is included in that release.

References

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