CVE-2026-93083

Setup denial via leaked mailbox channel

Published Sep 17, 2026 · Updated Sep 17, 2026

Mailbox leakage in Linux 6.4 allows local users to block ARM SCMI setup when an additional TX receiver channel request fails. The mailbox_chan_setup() function returns from that failure without releasing the primary channel, leaving it busy for later probe attempts. Exposure requires the ARM SCMI mailbox transport and this setup failure; the documented consequence is failed setup retries, not a system crash, and attacker control of the failure is unspecified.

CVSS severity2.0
Low
EPSS probability0.21%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Mailbox leakage in Linux 6.4 allows local users to block ARM SCMI setup when an additional TX receiver channel request fails. The mailbox_chan_setup() function returns from that failure without releasing the primary channel, leaving it busy for later probe attempts. Exposure requires the ARM SCMI mailbox transport and this setup failure; the documented consequence is failed setup retries, not a system crash, and attacker control of the failure is unspecified.

The record

CVE
CVE-2026-93083
Published
Sep 17, 2026
Updated
Sep 17, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Sep 17, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 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?

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

  1. Affected versionversion=6.4
  2. Affected versionversion=9f68ff79ec2cb303f360a35eef5dd8f1f0f817e1 <6f7c06744d53dc8e047725d411d7f915d9ec35ae
  3. Affected versionversion=9f68ff79ec2cb303f360a35eef5dd8f1f0f817e1 <717b8e972a667fc1bebe63cbcf0d58e692cbb491
  4. Affected versionversion=9f68ff79ec2cb303f360a35eef5dd8f1f0f817e1 <9958f55eace8b43713c9fc54dcf90e7cdefee413
  5. Affected versionversion=9f68ff79ec2cb303f360a35eef5dd8f1f0f817e1 <babb017cf5e4600c94c23ea87175a0380235a3ee

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linuxversion=6.4; version=9f68ff79ec2cb303f360a35eef5dd8f1f0f817e1 <6f7c06744d53dc8e047725d411d7f915d9ec35ae; version=9f68ff79ec2cb303f360a35eef5dd8f1f0f817e1 <717b8e972a667fc1bebe63cbcf0d58e692cbb491; version=9f68ff79ec2cb303f360a35eef5dd8f1f0f817e1 <9958f55eace8b43713c9fc54dcf90e7cdefee413; version=9f68ff79ec2cb303f360a35eef5dd8f1f0f817e1 <babb017cf5e4600c94c23ea87175a0380235a3ee

Published CVSS scores

1.9SUSECVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L
1.9Amazon LinuxCVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L
2.0SUSECVSS:4.0/AV:L/AC:H/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

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)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

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

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Your stack

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