CVE-2026-0543VulnerabilityPublished 13 Jan 2026

CVE-2026-0543: Elastic Kibana · Improper Input Validation

Affects Elastic KibanaSource 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 37% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Network
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: 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: 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 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
ElasticKibana	Affected >=8.0.0 <=8.19.9 >=7.0.0 <=7.17.29 >=9.0.0 <=9.1.9 >=9.2.0 <=9.2.3	Fixed in–

AI-suggested

1. Restrict access to Kibana's Email Connector functionality to only trusted and necessary users, enforcing the principle of least privilege to minimize the risk of exploitation. 2. Implement strong authentication and session management controls to prevent unauthorized access, including multi-factor authentication (MFA) for all users with view-level privileges. 3. Monitor Kibana logs and system resource usage for unusual spikes in memory allocation or service crashes that could indicate exploitation attempts. 4. Temporarily disable or limit the use of the Email Connector if feasible until a vendor patch or update is released. 5. Maintain an incident response plan that includes procedures for rapid manual restart of Kibana services to minimize downtime in case of exploitation. 6. Stay informed on Elastic's security advisories and apply patches or updates promptly once available. 7. Consider network segmentation and firewall rules to limit exposure of Kibana interfaces to trusted networks only. 8. Conduct regular security audits and penetration testing focusing on authenticated user actions to detect potential abuse of connector features.

Description

CVE-2026-0543 is a medium-severity vulnerability in Elastic Kibana's Email Connector caused by improper input validation of email address parameters. An authenticated attacker with view-level privileges can exploit this flaw by submitting a specially crafted email address, triggering excessive memory allocation that leads to complete service unavailability. The denial-of-service condition persists until a manual restart of the Kibana service is performed. This vulnerability affects multiple Kibana versions including 7.0.0, 8.0.0, 9.0.0, and 9.

Impact

For European organizations, the primary impact of CVE-2026-0543 is operational disruption due to denial-of-service of Kibana services. Kibana is widely used for log aggregation, monitoring, and analytics, often forming a critical component of security information and event management (SIEM) and operational dashboards. A successful exploit could halt visibility into system health and security events, delaying incident response and increasing risk exposure. This is particularly critical for sectors such as finance, telecommunications, energy, and government, where continuous monitoring is essential. The requirement for authenticated access limits the attack surface but insider threats or compromised credentials could still enable exploitation. The unavailability of Kibana until manual intervention increases downtime and operational costs. Additionally, organizations relying on automated alerting through the Email Connector may miss critical notifications during the outage. The absence of confidentiality or integrity impact reduces the risk of data breach but does not mitigate the operational consequences. European entities with stringent uptime requirements and regulatory obligations for monitoring may face compliance challenges if service disruptions occur.

CWE-20Improper Input Validation (opens in a new tab)
Class weaknessLikelihood of exploit: HighCWE Top 25 (2025): #18OWASP Top 10 A05:2025: Injection (opens in a new tab)
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
Architecture and Design · Attack Surface Reduction
Consider using language-theoretic security (LangSec) techniques that characterize inputs using a formal language and build "recognizers" for that language. This effectively requires parsing to be a distinct layer that effectively enforces a boundary between raw input and internal data representations, instead of…
Architecture and Design · Libraries or Frameworks
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 · Implementation · Attack Surface Reduction
Understand all the potential areas where untrusted inputs can enter the product, including but not limited to: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any…
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
Buffer Overflow via Environment Variables (opens in a new tab)
Server Side Include (SSI) Injection (opens in a new tab)
Cross Zone Scripting (opens in a new tab)
Command Line Execution through SQL Injection (opens in a new tab)
Object Relational Mapping Injection (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

discuss.elastic.co/t/kibana-8-19-10-9-1-10-9-2-4-security-update-esa-2026-08/384523 (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, 02:55 UTC

WeaknessesCWE-20

Technical details

References

Community reviews

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