CVE-2026-15565VulnerabilityPublished 11 Aug 2026Updated 25 Sep 2026

Buffer Overflow

Source GCVE Database

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Authoritative record:CVE-2026-15565· High 7.5

Not known to be exploited · CVSS 7.5 High : patch Red Hat JBoss Enterprise Application Platform 7.4 ELS on RHEL 7 soon.

Data as of 9 Nov 2026, 23:24 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

EPSS: 1.0% chance of exploitation in 30 days – higher than 63% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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 11 Aug 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 10 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-356w-cx4r-75hv

What to do

Patches and advisories

Affected software

Product	Affected	Fixed in
Red HatRed Hat JBoss Enterprise Application Platform 7.4.25	Affected–	Fixed in–
Red Hat JBoss Enterprise Application Platform 7.4 ELS on RHEL 7eap7-activemq-artemis	Affected–	Fixed in–
Red Hat JBoss Enterprise Application Platform 7.4 ELS on RHEL 7eap7-glassfish-jsf	Affected–	Fixed in–
Red Hat JBoss Enterprise Application Platform 7.4 ELS on RHEL 7eap7-ironjacamar	Affected–	Fixed in–
Red Hat JBoss Enterprise Application Platform 7.4 ELS on RHEL 7eap7-jackson-annotations	Affected–	Fixed in–
Red Hat JBoss Enterprise Application Platform 7.4 ELS on RHEL 7eap7-jackson-core	Affected–	Fixed in–

AI-suggested

A security update fixing this vulnerability is available in Red Hat JBoss Enterprise Application Platform version 7.4.25. Users should upgrade to this version or later to remediate the issue. No additional mitigations are specified by the vendor advisory.

Description

A vulnerability in Undertow allows a remote attacker to cause an Out of Memory condition on the WebSocket endpoint without authentication. This affects any @ServerEndpoint class with an @OnMessage method, enabling a denial of service (DoS) attack via a standard WebSocket handshake. The issue has a high severity score of 7.5 and impacts Red Hat JBoss Enterprise Application Platform 7.4. A security update is available in version 7.4.25 that addresses this flaw.

Impact

The vulnerability enables unauthenticated remote attackers to cause a denial of service by exhausting memory resources on the WebSocket endpoint. This results in service unavailability or crashes of affected applications using Undertow WebSocket endpoints with @ServerEndpoint classes containing @OnMessage methods. There is no impact on confidentiality or integrity.

Summary

CVE-2026-15565 describes a denial of service vulnerability in Undertow's WebSocket handling. An unauthenticated remote attacker can trigger an Out of Memory condition by exploiting the WebSocket endpoint on any @ServerEndpoint class that implements an @OnMessage method. This flaw allows resource exhaustion leading to service disruption. Red Hat's advisory confirms the issue affects Red Hat JBoss Enterprise Application Platform 7.4 and that a fix is included in the 7.4.25 release.

CWE-120Buffer Copy without Checking Size of Input (Classic Buffer Overflow) (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #11
The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer.
Requirements · Language Selection
Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Operation · Build and Compilation · Environment Hardening
Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index…
OWASP Cheat Sheets
Docker Security (opens in a new tab)
XML Security (opens in a new tab)
OWASP ASVS 4.0.3
V5.4.1 (opens in a new tab)
V14.1.2 (opens in a new tab)
V13.3.1 (opens in a new tab)
Attack patterns
Buffer Overflow via Environment Variables (opens in a new tab)
Overflow Buffers (opens in a new tab)
Client-side Injection-induced Buffer Overflow (opens in a new tab)
Filter Failure through Buffer Overflow (opens in a new tab)
MIME Conversion (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Patches and advisories

Affected software

Description

AI analysisMachine-generated, updated 4 Nov 2026, 13:58 UTC

WeaknessesCWE-120

Technical details

References

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