VulnerabilityPublished 17 Sep 2026Updated 21 Oct 2026

CVE-2026-93093: Linux kernel · firmware: arm_scmi: Publish channel state before callbacks

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in a1bc587568a4e373db76261dc9561dfc3653917f : update Linux kernel when convenient.

Data as of 26 Oct 2026, 20:07 UTC

Severity

Medium

Rated Medium by Threat Radar's AI analysis · CVSS not yet scored by NVD

EPSS: 0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in a1bc587568a4e373db76261dc9561dfc3653917f, 0314900dcdde044af0208fed212035dbfaa55843, 50e38091a657ad81385e2aea7e2575e17ac23d79 +2

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

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 5c8a47a5a91d4d6e185f758d61997613d9c5d6ac, < a1bc587568a4e373db76261dc9561dfc3653917f	Fixed in a1bc587568a4e373db76261dc9561dfc3653917f
LinuxLinux	Affected ≥ 5c8a47a5a91d4d6e185f758d61997613d9c5d6ac, < 0314900dcdde044af0208fed212035dbfaa55843	Fixed in 0314900dcdde044af0208fed212035dbfaa55843
LinuxLinux	Affected ≥ 5c8a47a5a91d4d6e185f758d61997613d9c5d6ac, < 50e38091a657ad81385e2aea7e2575e17ac23d79	Fixed in 50e38091a657ad81385e2aea7e2575e17ac23d79
LinuxLinux	Affected ≥ 5c8a47a5a91d4d6e185f758d61997613d9c5d6ac, < 6f3f532531e4a27d28a2240719d1b05ac11766c6	Fixed in 6f3f532531e4a27d28a2240719d1b05ac11766c6
LinuxLinux	Affected ≥ 5c8a47a5a91d4d6e185f758d61997613d9c5d6ac, < 1bea027f7ef6fb889628b16c568a5f7c07a51b30	Fixed in 1bea027f7ef6fb889628b16c568a5f7c07a51b30
LinuxLinux	Affected =5.7	Fixed in–

AI-suggested

A fix is available and has been applied in the Linux kernel commits identified by hashes a1bc587568a4e373db76261dc9561dfc3653917f, 0314900dcdde044af0208fed212035dbfaa55843, 50e38091a657ad81385e2aea7e2575e17ac23d79, 6f3f532531e4a27d28a2240719d1b05ac11766c6, and 1bea027f7ef6fb889628b16c568a5f7c07a51b30. Users should update to a Linux kernel version including these fixes. No additional mitigation steps are indicated.

Description

A vulnerability in the Linux kernel's arm_scmi firmware transport setup could lead to a NULL pointer dereference during early callback invocation. This occurs because the mailbox and SMC transport channel states are published after callbacks can be enabled, allowing a callback to access uninitialized pointers. The issue is fixed by assigning critical pointers before enabling callbacks and cleaning up on setup failure.

Impact

If exploited, this flaw could cause kernel faults due to NULL pointer dereferences in the arm_scmi transport RX callback path. This may lead to system instability or crashes. However, there is no indication of privilege escalation or remote code execution. No known exploits in the wild have been reported.

Summary

The Linux kernel arm_scmi firmware transport setup had a race condition where callbacks could be enabled before the transport channel state was fully published. Specifically, mailbox_chan_setup() and smc_chan_setup() could enable interrupt delivery or request IRQs before the SCMI mailbox channel state or cinfo pointers were visible. This allowed early or spurious callbacks to dereference NULL transport cinfo pointers or NULL handles, potentially causing faults. The fix involves assigning cinfo->handle before invoking transport setup callbacks, publishing transport-private channel state before requesting mailbox channels or IRQs, and clearing these pointers on setup failure. Additionally, mailbox setup resources are unwound on failure to prevent stale transport state.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Oct 2026, 20:07 UTC

Technical details

References

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