VulnerabilityPublished 31 Mar 2026

CVE-2026-4819: floragunn Search Guard FLX · Sensitive Data in Logs

Affects floragunn Search Guard FLXSource CVE Database V5

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Not known to be exploited · CVSS 4.9 Medium.

Data as of 30 Oct 2026, 06:59 UTC

CVSS 3.1 base score

4.9Medium

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 12% 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:H/I:N/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: High
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: None
Availability: None

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: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 31 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 29 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
floragunnSearch Guard FLX	Affected >=1.0.0 <=4.0.1	Fixed in–

AI-suggested

To mitigate CVE-2026-4819, organizations should first restrict access to audit logs to only trusted administrators and security personnel, employing strict file system permissions and network controls. Encrypt audit logs both at rest and in transit to prevent unauthorized reading. Monitor and audit access to logs to detect suspicious activity. Consider disabling or limiting audit logging of authentication events until a vendor patch or update is available. Upgrade Search Guard FLX to a version beyond 4.0.1 once a fix is released. If upgrading is not immediately possible, implement log redaction or filtering mechanisms to exclude sensitive credential information from logs. Additionally, enforce strong credential policies and multi-factor authentication for Kibana access to reduce the risk from compromised credentials. Regularly review and rotate credentials and audit configurations to minimize exposure. Finally, maintain an incident response plan that includes procedures for handling potential credential exposure through logs.

Description

In Search Guard FLX versions from 1.0.0 up to 4.0.1, the audit logging feature might log user credentials from users logging into Kibana.

Impact

The primary impact of CVE-2026-4819 is the potential exposure of user credentials through audit logs, which compromises confidentiality. If attackers gain access to these logs, they could harvest credentials to escalate privileges or move laterally within an organization’s infrastructure. This exposure can lead to unauthorized access to Kibana dashboards and Elasticsearch data, potentially leaking sensitive business intelligence or operational data. Although the vulnerability does not directly affect system integrity or availability, the indirect consequences of credential compromise can be severe, including data breaches and compliance violations. Organizations relying on Search Guard FLX for security hardening may find their audit logs, which are critical for monitoring and compliance, become a liability if not properly secured. The medium CVSS score reflects that exploitation requires high privileges, limiting the attack surface to insiders or attackers who have already gained some level of access. However, given the widespread use of Elasticsearch and Kibana in enterprise environments globally, the risk remains significant for organizations that do not adequately protect their logs or promptly update their software.

CWE-532Insertion of Sensitive Information into Log File (opens in a new tab)
Base weaknessLikelihood of exploit: MediumOWASP Top 10 A09:2025: Security Logging & Alerting Failures (opens in a new tab)
The product writes sensitive information to a log file.
Architecture and Design · Implementation
Consider seriously the sensitivity of the information written into log files. Do not write secrets into the log files.
Distribution
Remove debug log files before deploying the application into production.
Operation
Protect log files against unauthorized read/write.
OWASP Cheat Sheets
Application Logging Vocabulary (opens in a new tab)
Logging (opens in a new tab)
OWASP ASVS 4.0.3
V7.1.1 (opens in a new tab)
V7.1.2 (opens in a new tab)
V8.3.5 (opens in a new tab)
Attack patterns
Fuzzing for application mapping (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-522Insufficiently Protected Credentials (opens in a new tab)
Class weaknessOWASP Top 10 A06:2025: Insecure Design (opens in a new tab)
The product transmits or stores authentication credentials, but it uses an insecure method that is susceptible to unauthorized interception and/or retrieval.
Architecture and Design
Use an appropriate security mechanism to protect the credentials.
Architecture and Design
Make appropriate use of cryptography to protect the credentials.
Implementation
Use industry standards to protect the credentials (e.g. LDAP, keystore, etc.).
OWASP Cheat Sheets
Secure Design Principles (opens in a new tab)
OWASP ASVS 4.0.3
V2.10.3 (opens in a new tab)
V2.8.5 (opens in a new tab)
V2.8.4 (opens in a new tab)
Attack patterns
Session Sidejacking (opens in a new tab)
Signature Spoofing by Key Theft (opens in a new tab)
Password Recovery Exploitation (opens in a new tab)
Kerberoasting (opens in a new tab)
Modify Existing Service (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 31 Mar 2026, 15:38 UTC

WeaknessesCWE-532, CWE-522

Technical details

References

Community reviews

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