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HIGH severity

CVE-2026-49091 — elasticsearch

HIGH

CVE-2026-49091 is a high-severity (CVSS 8) CWE-116 vulnerability. A fix is available — see the affected versions and patch details below.

Improper Output Neutralization for Logs in Kibana Leading to Log Injection

Published
Jul 1, 2026
Updated
Aug 12, 2026
Affected
1 product
Patched
See advisory
Exploits
None indexed
Exploitation data as of Sep 30, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • A successful exploit gives an attacker total control of the affected component, not partial access.
  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-49091.

EPSS Exploitation Probability

via FIRST.org ↗
0.3%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs22th percentile — riskier than 22% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2026-49091 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 381,682 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Description

Improper Output Neutralization for Logs (CWE-117) in Kibana can lead to log injection via Log Injection-Tampering-Forging (CAPEC-93). An attacker can supply specially crafted input that is written to log files without proper neutralization. When the log files are subsequently viewed in a terminal that interprets control sequences, the injected content may alter the displayed log data.

Affected Products

1 product · 2 configurations
Application
kibanaelastic
≥ 8.0.0 && < 8.11.1
range

Detection & mitigation playbook

Vulnerability

  1. Detect

    Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).

  2. Fix

    Upgrade the affected component to the fixed release for CVE-2026-49091, or apply your distribution's backported patch — distro builds are often patched at an older version number, so check your vendor's advisory rather than the upstream version alone.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

Improper Output Neutralization for Logs (CWE-117) in Kibana can lead to log injection via Log Injection-Tampering-Forging (CAPEC-93). An attacker can supply specially crafted input that is written to log files without proper neutralization. When the log files are subsequently viewed in a terminal that interprets control sequences, the injected content may alter the displayed log data.
O3 Security · Impact-Aware SCA

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CVE-2026-49091: elasticsearch (High 8) | O3 Security