VulnerabilityPublished 26 Feb 2026

CVE-2026-26936: Elastic Kibana · ReDoS

Affects Elastic KibanaSource CVE Database V5

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Not known to be exploited · CVSS 4.9 Medium.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 3.1 base score

4.9Medium

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

EPSS: 0.3% chance of exploitation in 30 days – higher than 31% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: High
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: High: The attacker is authorized with (i.e., requires) privileges that provide significant (e.g., administrative) control over the vulnerable component that could affect component-wide settings and files.
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 >=9.0.0 <=9.2.4 >=8.0.0 <=8.19.10	Fixed in–

AI-suggested

To mitigate CVE-2026-26936, organizations should first verify if their Kibana installations are running affected versions (8.0.0 or 9.0.0) and plan for immediate upgrades once patches become available from Elastic. Until patches are released, restrict access to Kibana's AI Inference Anonymization Engine to only trusted, highly privileged users and monitor for unusual CPU or memory usage patterns indicative of regex blowup attacks. Implement strict input validation and sanitization on any inputs processed by the anonymization engine to reduce the risk of malicious regex patterns. Employ network segmentation and firewall rules to limit exposure of Kibana interfaces to internal networks only. Additionally, enforce strong authentication and privilege management policies to minimize the risk of compromised accounts being used to exploit this vulnerability. Consider deploying runtime application self-protection (RASP) or Web Application Firewalls (WAFs) capable of detecting and blocking anomalous regex processing patterns. Finally, maintain comprehensive logging and alerting to detect early signs of exploitation attempts.

Description

Inefficient Regular Expression Complexity (CWE-1333) in the AI Inference Anonymization Engine in Kibana can lead Denial of Service via Regular Expression Exponential Blowup (CAPEC-492).

Impact

The primary impact of CVE-2026-26936 is denial of service, which can disrupt the availability of Kibana dashboards and AI inference anonymization features. For organizations relying on Kibana for real-time data visualization, monitoring, and AI-driven data anonymization, this could lead to significant operational downtime, delayed decision-making, and potential compliance issues if anonymization processes fail. Since the attack requires authenticated access with high privileges, insider threats or compromised privileged accounts pose the greatest risk. The vulnerability does not affect confidentiality or integrity, but the loss of availability can indirectly impact business continuity and incident response capabilities. In large-scale deployments, especially those integrated into critical infrastructure or financial services, even temporary outages can have cascading effects. The absence of known exploits reduces immediate risk, but the medium severity and ease of triggering resource exhaustion warrant proactive mitigation to prevent exploitation.

CWE-1333Inefficient Regular Expression Complexity (opens in a new tab)
Base weaknessLikelihood of exploit: High
The product uses a regular expression with a worst-case computational complexity that is inefficient and possibly exponential.
Architecture and Design
Use regular expressions that do not support backtracking, e.g. by removing nested quantifiers.
System Configuration
Set backtracking limits in the configuration of the regular expression implementation, such as PHP's pcre.backtrack_limit. Also consider limits on execution time for the process.
Implementation
Do not use regular expressions with untrusted input. If regular expressions must be used, avoid using backtracking in the expression.
OWASP Cheat Sheets
File Upload (opens in a new tab)
OWASP ASVS 4.0.3
V12.1.1 (opens in a new tab)
Attack patterns
Regular Expression Exponential Blowup (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

discuss.elastic.co/t/kibana-8-19-11-9-2-5-security-update-esa-2026-14/385250 (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-1333

Technical details

References

Community reviews

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