VulnerabilityPublished 26 Feb 2026

CVE-2026-26934: 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 30 Oct 2026, 11:52 UTC

CVSS 3.1 base score

6.5Medium

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

EPSS: 0.3% chance of exploitation in 30 days – higher than 24% 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 26 Feb 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 >=8.18.0 <=8.19.11 >=9.0.0 <=9.2.5 >=9.3.0 <=9.3.0	Fixed in–

AI-suggested

To mitigate CVE-2026-26934, organizations should implement the following specific measures: 1) Apply any available patches or updates from Elastic as soon as they are released to address the input validation flaw. 2) Enforce strict input validation and sanitization on all user inputs, particularly those involving quantity or size parameters, to prevent malformed payloads from triggering resource exhaustion. 3) Implement rate limiting and throttling on API endpoints accessible to view-only users to reduce the risk of abuse through repeated malformed requests. 4) Monitor Kibana resource usage metrics closely to detect unusual spikes in CPU, memory, or request rates that could indicate exploitation attempts. 5) Restrict view-only privileges to trusted users and regularly audit user accounts to minimize the risk of insider threats. 6) Consider deploying Web Application Firewalls (WAFs) or API gateways with custom rules to detect and block suspicious payload patterns. 7) Isolate Kibana instances in segmented network zones to limit the blast radius of potential DoS attacks. 8) Maintain comprehensive logging and alerting to enable rapid detection and response to anomalous activity related to this vulnerability.

Description

Improper Validation of Specified Quantity in Input (CWE-1284) in Kibana can allow an authenticated attacker with view-only privileges to cause a Denial of Service via Input Data Manipulation (CAPEC-153). An attacker can send a specially crafted, malformed payload causing excessive resource consumption and resulting in Kibana becoming unresponsive or crashing.

Impact

The primary impact of CVE-2026-26934 is denial of service, which affects the availability of Kibana instances. Organizations relying on Kibana for real-time data visualization, monitoring, and alerting could experience service outages or degraded performance, potentially delaying incident response and operational decision-making. Since the vulnerability can be exploited by users with only view-only privileges, insider threats or compromised low-privilege accounts could be leveraged to disrupt services. This could affect sectors such as finance, healthcare, telecommunications, and critical infrastructure where Kibana is widely used for monitoring large-scale systems. The disruption could cascade into broader operational impacts, including delayed detection of security incidents or system failures. However, the vulnerability does not impact confidentiality or integrity, limiting the scope of damage to availability concerns. The absence of known exploits reduces immediate risk but does not eliminate the threat, especially in environments with many authenticated users.

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-8-19-12-9-2-6-9-3-1-security-update-esa-2026-12/385248 (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Feb 2026, 17:43 UTC

WeaknessesCWE-1284

Technical details

References

Community reviews

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