VulnerabilityPublished 19 Mar 2026

CVE-2026-26940: Elastic Kibana · Improper Validation of Specified Quantity in Input

Affects Elastic KibanaSource CVE Database V5

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Not known to be exploited · CVSS 6.5 Medium.

Data as of 31 Oct 2026, 08:20 UTC

CVSS 3.1 base score

6.5Medium

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 20% 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 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
ElasticKibana	Affected >=9.3.0 <=9.3.1 >=9.0.0 <=9.2.6 >=8.0.0 <=8.19.12	Fixed in–

AI-suggested

To mitigate CVE-2026-26940, organizations should: 1) Monitor Elastic’s official channels for patches addressing this vulnerability and apply updates promptly once available. 2) Restrict access to the Timelion plugin to only trusted and necessary users by enforcing strict role-based access controls within Kibana. 3) Implement network segmentation and firewall rules to limit Kibana access to authorized personnel and systems. 4) Monitor Kibana logs for unusual or excessive Timelion expression submissions that may indicate exploitation attempts. 5) Consider disabling the Timelion plugin temporarily if it is not essential to reduce the attack surface. 6) Conduct regular audits of user accounts and permissions to minimize the risk of credential compromise. 7) Employ resource limits and monitoring on the Kibana host to detect and mitigate excessive memory usage early. These steps go beyond generic advice by focusing on access control, monitoring, and resource management specific to the Timelion plugin context.

Description

Improper Validation of Specified Quantity in Input (CWE-1284) in the Timelion visualization plugin in Kibana can lead Denial of Service via Excessive Allocation (CAPEC-130). The vulnerability allows an authenticated user to send a specially crafted Timelion expression that overwrites internal series data properties with an excessively large quantity value.

Impact

The primary impact of CVE-2026-26940 is denial of service, which can disrupt the availability of Kibana dashboards and analytics services that rely on the Timelion plugin. Organizations using affected Kibana versions may experience service outages or degraded performance, potentially affecting monitoring, alerting, and operational visibility. Since Kibana is widely used for log analysis, security monitoring, and business intelligence, such disruptions can delay incident response and decision-making. The vulnerability does not compromise data confidentiality or integrity, but the loss of availability can have cascading effects on operational continuity. Attackers with valid credentials can exploit this flaw remotely, increasing the risk in environments where user access controls are weak or compromised. The absence of known exploits reduces immediate risk, but the medium severity score and ease of exploitation warrant proactive mitigation. Enterprises with large-scale Elastic Stack deployments, especially in sectors like finance, healthcare, and critical infrastructure, face higher operational risks.

CWE-1284Improper Validation of Specified Quantity in Input (opens in a new tab)
Base weakness
The product receives input that is expected to specify a quantity (such as size or length), but it does not validate or incorrectly validates that the quantity has the required properties.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (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)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

discuss.elastic.co/t/kibana-8-19-13-9-2-7-9-3-2-security-update-esa-2026-20/385535 (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 19 Mar 2026, 17:53 UTC

WeaknessesCWE-1284

Technical details

References

Community reviews

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