CVE-2026-91147Network attack vectorHinoki check available

Web-service crash via exact URL-root prefix

Published Sep 18, 2026 · Updated Sep 18, 2026

Reachable assertion in Red Hat cockpit-ws allows remote attackers to crash the Cockpit web service with a crafted URL-root request. The URL-root request handler accepts the exact configured prefix without a trailing slash and reaches an assertion that terminates cockpit-ws. Exploitation requires non-default WebService.UrlRoot configuration and a path that reaches cockpit-ws without proxy normalization or redirection, interrupting only the Cockpit web service.

CVSS severity5.9
Medium
EPSS probability0.40%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Reachable assertion in Red Hat cockpit-ws allows remote attackers to crash the Cockpit web service with a crafted URL-root request. The URL-root request handler accepts the exact configured prefix without a trailing slash and reaches an assertion that terminates cockpit-ws. Exploitation requires non-default WebService.UrlRoot configuration and a path that reaches cockpit-ws without proxy normalization or redirection, interrupting only the Cockpit web service.

The record

CVE
CVE-2026-91147
Published
Sep 18, 2026
Updated
Sep 18, 2026
Vendor
Commonhaus Foundation
Product
Red Hat Enterprise Linux 10
Classifications
CWE-617, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 18, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Commonhaus Foundation · Red Hat Enterprise Linux 10Affected versions are unavailable in this record.
Commonhaus Foundation · Red Hat Enterprise Linux 8Affected versions are unavailable in this record.
Commonhaus Foundation · Red Hat Enterprise Linux 7Affected versions are unavailable in this record.
Commonhaus Foundation · Red Hat Enterprise Linux 9Affected versions are unavailable in this record.
Commonhaus Foundation · Red Hat OpenShift Dev SpacesAffected versions are unavailable in this record.

Published CVSS scores

5.9Red HatCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/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.

Activity data is delayed. The latest report is Sep 28, 2026.

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

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-617Reachable Assertion
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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