VulnerabilityPublished 17 Sep 2026Updated 5 Oct 2026

CVE-2026-93083: Linux kernel · firmware: arm_scmi: Unwind TX receiver mailbox setup failure

Affects Linux kernelSource GCVE Database

Authoritative record:CVE-2026-93083

Not known to be exploited.

Data as of 26 Oct 2026, 14:05 UTC

Severity

Medium

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.2% chance of exploitation in 30 days – higher than 10% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

Exploitation evidence

Disclosed: evidence found.
CVE published 17 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Ubuntu 26.04 LTSlinux`pkg:deb/ubuntu/linux?arch=source&distro=resolute`Other threats	Affected 6.17.0-5.5 – 7.0.0-38.38 23 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-aws`pkg:deb/ubuntu/linux-aws?arch=source&distro=resolute`Other threats	Affected 6.17.0-1002.2 – 7.0.0-1014.14 15 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-azure`pkg:deb/ubuntu/linux-azure?arch=source&distro=resolute`Other threats	Affected 6.17.0-1003.3 – 7.0.0-1017.17 15 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-azure-fde`pkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resolute`Other threats	Affected 7.0.0-1003.3 – 7.0.0-1016.16 9 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-gcp`pkg:deb/ubuntu/linux-gcp?arch=source&distro=resolute`Other threats	Affected 6.17.0-1002.2 – 7.0.0-1014.14 13 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-gke`pkg:deb/ubuntu/linux-gke?arch=source&distro=resolute`Other threats	Affected 7.0.0-1002.3 – 7.0.0-1008.9 6 affected builds	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A fix has been implemented in the Linux kernel to properly unwind the primary mailbox channel before returning an error in mailbox_chan_setup(). Users should apply the official kernel updates that include this fix for the affected linux-hwe-edge versions. No additional mitigation is indicated beyond applying the patch.

Description

A vulnerability in the Linux kernel's arm_scmi firmware component was resolved. The issue involved the mailbox_chan_setup() function, which could leave the primary TX receiver mailbox channel allocated if a secondary channel request failed, potentially causing the channel to remain busy and interfere with later probe attempts. This flaw was fixed by ensuring the primary mailbox channel is properly unwound before returning an error. The vulnerability affects specific versions of the linux-hwe-edge kernel and has been assigned CVE-2026-93083. The severity is assessed as medium.

Impact

If the secondary TX receiver channel request fails, the primary mailbox channel remains allocated and busy, which can cause probe deferral or setup failures in the arm_scmi firmware component. This may impact device initialization or communication relying on this channel, potentially leading to degraded functionality or resource exhaustion in affected systems.

Summary

The Linux kernel's arm_scmi firmware component had a vulnerability in mailbox_chan_setup() where after successfully acquiring the primary TX receiver mailbox channel, a subsequent request for an additional unidirectional TX receiver channel could fail. If this second request failed, the function returned immediately without releasing the primary channel, leaving it allocated and busy. This could cause probe deferral or other setup failures to leave the channel busy for later probe attempts. The fix involves unwinding the primary mailbox channel before returning the error to prevent resource leakage.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 24 Oct 2026, 23:29 UTC

Technical details

References

Community reviews

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