CVE-2025-46827Network attack vector

Session takeover via unsanitized remediation-step HTML

Published May 7, 2025 · Updated May 7, 2025

Stored cross-site scripting in Graylog Open Server before 6.0.14 and 6.1.0 through 6.1.9 allows remote authenticated users to steal session cookies. An Event Definition Remediation Step accepts attacker-supplied HTML containing a form that submits a viewing user's session cookie to an active Graylog input without sufficient sanitization. The attacker needs permission to create event definitions, the victim must view alerts, and an input capable of receiving form data must be active; the stolen cookie enables session takeover.

CVSS severity8.0
High
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Stored cross-site scripting in Graylog Open Server before 6.0.14 and 6.1.0 through 6.1.9 allows remote authenticated users to steal session cookies. An Event Definition Remediation Step accepts attacker-supplied HTML containing a form that submits a viewing user's session cookie to an active Graylog input without sufficient sanitization. The attacker needs permission to create event definitions, the victim must view alerts, and an input capable of receiving form data must be active; the stolen cookie enables session takeover.

The record

CVE
CVE-2025-46827
Published
May 7, 2025
Updated
May 7, 2025
Vendor
Graylog
Product
Graylog Open Server
Classifications
T1539
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 7, 2025CVE publishedPublication date reported by the CVE source.
  2. May 7, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 6.0.14
  2. Affected versionversion=>= 6.1.0, < 6.1.10

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Graylog · Graylog Open Serverversion=< 6.0.14; version=>= 6.1.0, < 6.1.10

Published CVSS scores

8.0GraylogCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1539Steal Web Session Cookie

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo