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CVE-2026-91150

Cockpit: cockpit: denial of service via unbounded fragmented websocket messages

No known exploitation. EPSS puts it in the 60th percentile. Fixed versions are out.

CVSS 3.17.5HighEPSS percentile60th0.9% chance in 30 daysCISA KEVNot listedNo confirmed exploitation
No public exploit knownFix3 products5 fixed builds listed below
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Published Updated Sources: CVE.org, NVD

NVD CVE.org

What to do

Find your product and version, then upgrade to the build on the right.

  • Red Hat Enterprise Linux 10Fixed builds0:366.1.1-1.el10_3, 0:310.10.2-1.el8_10, 0:366.1.1-1.el9_9Stated by: CVE record
  • Red Hat Enterprise Linux 10.2 Extended Update SupportFixed builds0:356.4.1-1.el10_2Stated by: CVE record
  • Red Hat Enterprise Linux 9.8 Extended Update SupportFixed builds0:356.4.1-1.el9_8Stated by: CVE record

Versions as the sources state them. Full version matrix after sign-in

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What it is

From the CVE record

A flaw was found in Cockpit. This vulnerability allows a remote attacker, without prior authentication, to send specially crafted fragmented WebSocket messages. These messages accumulate without a total-size limit, leading to unbounded memory exhaustion and a denial of service in the `cockpit-ws` service.

In plain language

No plain-language summary for this CVE yet.

Exploitation

Where each signal puts this CVE on the scale from published to confirmed exploited.

EPSS60th
CISA KEV

Not in the catalog. CISA has not confirmed exploitation.

Public exploits

No public exploit or proof of concept found in the sources we track.

EPSS

0.9% chance of exploitation activity in the next 30 days, which ranks it in the 60th percentile of scored CVEs.

Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.

Lifecycle

6 events over 1 day, from the signal feeds we watch.

  1. Record updatedrecord updated
  2. Publishedweakness classified, att&ck mapped, record updated

Affected products

And 3 more affected products. See all after sign-in

Technical detail

CVSS 3.1 vector

Open in the CVSS calculator

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Scored 7.5 by NVD.

How it is reached

  • Attack Vector NetworkExploitable remotely over the network without any special conditions
  • Attack Complexity LowNo special conditions — the attack can be reliably reproduced
  • Privileges Required NoneNo authentication required — anyone can exploit this
  • User Interaction NoneNo user interaction needed — fully automated exploitation

Scope

  • Scope UnchangedImpact is limited to the vulnerable component itself

Impact if exploited

  • Confidentiality NoneNo confidentiality impact
  • Integrity NoneNo integrity impact
  • Availability HighTotal denial of service — the component is completely unavailable

Weaknesses

ATT&CK techniques

Mapped from the weaknesses above (CWE to ATT&CK), not observed in attacks.

Sources

References in the record

And 6 more references. See all after sign-in

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