CVE-2026-0528VulnerabilityPublished 13 Jan 2026

CVE-2026-0528: Elastic Metricbeat · Improper Validation of Array Index

Affects Elastic MetricbeatSource CVE Database V5

Not known to be exploited · CVSS 6.5 Medium.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score

6.5Medium

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

EPSS: 0.4% chance of exploitation in 30 days – higher than 36% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Adjacent
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: 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: 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 13 Jan 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 2026-10-25.

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 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 >=7.0.0 <=7.17.29 >=8.0.0 <=8.19.9 >=9.0.0 <=9.1.9 >=9.2.0 <=9.2.3	Fixed in–

AI-suggested

Organizations should prioritize upgrading Metricbeat to patched versions once available from Elastic. In the interim, network-level controls should be implemented to restrict access to Metricbeat endpoints, limiting exposure to trusted hosts and monitoring systems only. Deploying Web Application Firewalls (WAFs) or Intrusion Prevention Systems (IPS) with signatures or anomaly detection for malformed payloads targeting Graphite, Zookeeper, and Prometheus metricsets can reduce attack surface. Monitoring logs for unusual or malformed metric data can provide early warning of exploitation attempts. Employing rate limiting and input validation at the network edge or proxy level can further mitigate malformed data injection. Additionally, organizations should review their incident response plans to account for potential monitoring outages and ensure alternative alerting mechanisms are in place. Regularly auditing Metricbeat configurations and minimizing unnecessary enabled modules reduces exposure. Finally, engaging with Elastic support and subscribing to security advisories ensures timely awareness of patches and updates.

Description

CVE-2026-0528 is a medium severity vulnerability in Elastic Metricbeat affecting versions 7.0.0 through 9.2.0. It involves improper validation of array indices (CWE-129) in the Graphite and Zookeeper server metricsets, and improper input validation (CWE-20) in the Prometheus helper module. An attacker can exploit this by sending specially crafted malformed payloads or metric data, causing a Denial of Service (DoS) condition. The vulnerability requires network access but no authentication or user interaction. While no known exploits are currently in the wild, the flaw can disrupt metric collection and monitoring services. European organizations relying on Metricbeat for infrastructure monitoring may experience service outages or degraded observability.

Impact

For European organizations, the primary impact of CVE-2026-0528 is the potential disruption of monitoring and observability infrastructure. Metricbeat is commonly deployed to collect metrics from various services and forward them to Elasticsearch or other backends. A successful DoS attack could cause loss of metric data, delayed alerts, and blind spots in monitoring dashboards, which are critical for detecting and responding to operational issues and security incidents. This can degrade the overall security posture and operational resilience. Industries with stringent uptime and compliance requirements, such as finance, healthcare, and critical infrastructure, may face increased risk of service degradation or regulatory non-compliance due to monitoring gaps. Additionally, organizations using Metricbeat in multi-tenant or cloud environments may experience cascading effects if monitoring failures propagate unnoticed. Although the vulnerability does not directly expose sensitive data or allow code execution, the availability impact on monitoring services can indirectly increase risk by delaying detection of other attacks or failures.

CWE-129Improper Validation of Array Index (opens in a new tab)
Variant weaknessLikelihood of exploit: HighOWASP Top 10 A05:2025: Injection (opens in a new tab)
The product uses untrusted input when calculating or using an array index, but the product does not validate or incorrectly validates the index to ensure the index references a valid position within the array.
Architecture and Design · Input Validation
Use an input validation framework such as Struts or the OWASP ESAPI Validation API. Note that using a framework does not automatically address all input validation problems; be mindful of weaknesses that could arise from misusing the framework itself (CWE-1173).
Architecture and Design
For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks…
Requirements · Language Selection
Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
Injection Prevention (opens in a new tab)
SQL Injection Prevention (opens in a new tab)
Injection Prevention in Java (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
Attack patterns
Overflow Buffers (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

discuss.elastic.co/t/metricbeat-8-19-10-9-1-10-9-2-4-security-update-esa-2026-01/384519 (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 21 Jan 2026, 02:54 UTC

WeaknessesCWE-129

Technical details

References

Community reviews

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