VulnerabilityPublished 18 Oct 2026Updated 21 Oct 2026

CVE-2026-98773: Linux kernel · USB: cdc-acm: skip URB restart in port_shutdown if disconnected

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in dc614d6bc991740d41d5a99ac7765c4b675dda88 : patch Linux kernel soon.

Data as of 26 Oct 2026, 20:31 UTC

Severity

High

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

EPSS: 0.1% chance of exploitation in 30 days – higher than 5% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in dc614d6bc991740d41d5a99ac7765c4b675dda88, d86775e79838d7d2e38ccf506a7d0f8e2dd4d5d0, a0ed07b5bbb2d8fcef86810453216070691816e7 +8

Exploitation evidence

Disclosed: evidence found.
CVE published 18 Oct 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 >=6.6.136 <6.6.160 >=6.12.83 <6.12.113 >=6.18.24 <6.18.56 >=6.1.175 <6.2 >=6.19.14 <6.20 >=7.0.1 <7.1	Fixed in dc614d6bc991740d41d5a99ac7765c4b675dda88 d86775e79838d7d2e38ccf506a7d0f8e2dd4d5d0 a0ed07b5bbb2d8fcef86810453216070691816e7 9742905d9ed5bf23ebe4c100dec80b6bc50fb522 420ca35af891d33522cc08504768ccd60a4c450a 7.1 6.20 6.18.56 6.12.113 6.6.160 6.2
LinuxLinux	Affected =7.1	Fixed in–

AI-suggested

A fix is available and has been applied in Linux kernel versions 6.6.160, 6.12.113, 6.18.56, 6.20, 7.1, and later. Users and administrators should update to these fixed versions to remediate the vulnerability.

Description

A use-after-free vulnerability exists in the Linux kernel's USB cdc-acm driver due to improper handling of URB restarts during port shutdown when a device is disconnected. This flaw occurs because the driver may resubmit USB Request Blocks (URBs) after they have been freed, leading to potential memory corruption.

Impact

This vulnerability can lead to use-after-free memory corruption in the USB cdc-acm driver, which may cause kernel crashes or potentially allow an attacker to execute arbitrary code in kernel context if exploited. However, no known exploits in the wild have been reported.

Summary

The Linux kernel's USB cdc-acm driver had a vulnerability where acm_port_shutdown() would unconditionally call acm_unpoison_urbs() and resubmit control and read URBs even if the device was disconnected. Concurrently, acm_disconnect() frees these URBs and their DMA buffers, causing use-after-free conditions in acm_ctrl_irq() or acm_read_bulk_callback() when accessing freed DMA memory. The fix involves checking the acm->disconnected flag after draining the delayed anchor and returning early to avoid resubmitting URBs during disconnect, ensuring that poisoned URBs remain poisoned and are not resubmitted.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Oct 2026, 20:31 UTC

Technical details

References

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