VulnerabilityPublished 19 Mar 2026

CVE-2026-26931: Elastic Metricbeat · Excessive Memory Allocation

Affects Elastic MetricbeatSource CVE Database V5

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Not known to be exploited · CVSS 5.7 Medium.

Data as of 30 Oct 2026, 20:25 UTC

CVSS 3.1 base score

5.7Medium

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

EPSS: 0.1% chance of exploitation in 30 days – higher than 8% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Adjacent
Attack Complexity: Low
Privileges Required: Low
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: Adjacent: The vulnerable component is bound to the network stack, but the attack is limited at the protocol level to a logically adjacent topology. This can mean an attack must be launched from the same shared physical (e.g., Bluetooth or IEEE 802.11) or logical (e.g., local IP subnet) network, or from within a secure or otherwise limited administrative domain (e.g., MPLS, secure VPN to an administrative network zone).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
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 19 Mar 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 30 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.
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.

What to do

Affected software

Product	Affected	Fixed in
ElasticMetricbeat	Affected >=8.0.0 <=8.19.12	Fixed in–

AI-suggested

To mitigate CVE-2026-26931, organizations should first check for and apply any official patches or updates from Elastic as they become available. In the absence of patches, administrators should consider restricting network access to the Prometheus remote_write HTTP handler to trusted sources only, using firewalls or network segmentation to limit exposure. Implementing rate limiting or request size validation at the network or application layer can help prevent excessive allocation attempts. Monitoring Metricbeat resource usage and setting alert thresholds for abnormal memory consumption can provide early warning signs of exploitation attempts. Additionally, running Metricbeat with the least privileges necessary reduces the risk posed by compromised accounts. Reviewing and hardening configuration settings related to Prometheus remote_write endpoints, including disabling unused features, can further reduce attack surface. Finally, organizations should maintain an incident response plan that includes steps for rapid recovery from DoS conditions affecting monitoring infrastructure.

Description

Memory Allocation with Excessive Size Value (CWE-789) in the Prometheus remote_write HTTP handler in Metricbeat can lead Denial of Service via Excessive Allocation (CAPEC-130).

Impact

The primary impact of CVE-2026-26931 is a Denial of Service condition caused by excessive memory allocation in Metricbeat's Prometheus remote_write handler. This can lead to service crashes or severe performance degradation, disrupting monitoring and telemetry data collection. Organizations relying on Metricbeat for infrastructure and application monitoring may experience blind spots in observability, delaying detection and response to other incidents. The vulnerability does not compromise data confidentiality or integrity but can indirectly affect operational stability and incident management. Since Metricbeat is often deployed in critical environments for real-time metrics, the availability impact can cascade, affecting dependent systems and operational decision-making. The requirement for low privileges and network access means that internal or semi-trusted users could exploit this flaw, increasing risk in multi-tenant or segmented network environments. Although no known exploits exist currently, the medium severity and ease of triggering excessive allocation warrant proactive mitigation to avoid potential service outages.

CWE-789Memory Allocation with Excessive Size Value (opens in a new tab)
Variant weakness
The product allocates memory based on an untrusted, large size value, but it does not ensure that the size is within expected limits, allowing arbitrary amounts of memory to be allocated.
Implementation · Architecture and Design
Perform adequate input validation against any value that influences the amount of memory that is allocated. Define an appropriate strategy for handling requests that exceed the limit, and consider supporting a configuration option so that the administrator can extend the amount of memory to be used if necessary.
Operation
Run your program using system-provided resource limits for memory. This might still cause the program to crash or exit, but the impact to the rest of the system will be minimized.
OWASP Cheat Sheets
Abuse Case (opens in a new tab)
OWASP ASVS 4.0.3
V8.1.4 (opens in a new tab)
V13.4.1 (opens in a new tab)
V11.1.4 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

discuss.elastic.co/t/metricbeat-8-19-13-9-2-5-security-update-esa-2026-09/385532 (opens in a new tab)

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 19 Mar 2026, 17:23 UTC

WeaknessesCWE-789

Technical details

References

Community reviews

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