CVE-2025-27533: Apache ActiveMQ · Excessive Memory Allocation

Attack Vector: Network

The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, 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

The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.

Attack Requirements: Present

The successful attack depends on the presence of specific deployment and execution conditions of the vulnerable system that enable the attack. These include: a race condition must be won to successfully exploit the vulnerability (the successfulness of the attack is conditioned on execution conditions that are not under full control of the attacker, or the attack may need to be launched multiple times against a single target before being successful); the attacker must inject themselves into the logical network path between the target and the resource requested by the victim (e.g. vulnerabilities requiring an on-path attacker).

Privileges Required: High

The attacker requires privileges that provide significant (e.g., administrative) control over the vulnerable system allowing full access to the vulnerable system’s settings and files.

User Interaction: None

The vulnerable system can be exploited without interaction from any human user, other than the attacker.

Vulnerable system confidentiality: None

There is no loss of confidentiality within the Vulnerable System.

Vulnerable system integrity: None

There is no loss of integrity within the Vulnerable System.

Vulnerable system availability: High

There is a total loss of availability, resulting in the attacker being able to fully deny access to resources in the Vulnerable System; 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 Vulnerable System (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).

Subsequent system confidentiality: None

There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.

Subsequent system integrity: None

There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.

Subsequent system availability: High

There is a total loss of availability, resulting in the attacker being able to fully deny access to resources in the Subsequent System; 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 Subsequent System (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).

Automatable: Yes

Attackers can reliably automate all 4 steps of the kill chain. These steps are reconnaissance, weaponization, delivery, and exploitation (e.g., the vulnerability is “wormable”).

Recovery: Automatic

The system recovers services automatically after an attack has been performed.

Value Density: Diffuse

The vulnerable system has limited resources. That is, the resources that the attacker will gain control over with a single exploitation event are relatively small. An example of Diffuse (think: limited) Value Density would be an attack on a single email client vulnerability.

Vulnerability Response Effort: Moderate

The actions required to respond to a vulnerability require some effort on behalf of the consumer and could cause minimal service impact to implement. Examples include: simple remote update, disabling of a subsystem, or a low-touch software upgrade such as a driver update.

Provider Urgency: Red

Provider has assessed the impact of this vulnerability as having the highest urgency.

Definitions: FIRST CVSS v4.0 specification.