VulnerabilityPublished 19 Jul 2026

CVE-2026-63905: Linux kernel · usbip: vudc: Fix use after free bug in vudc_remove due to race condition

Affects Linux kernelSource GCVE Database

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Not known to be exploited.

Data as of 30 Oct 2026, 15:36 UTC

Severity

High

Rated High by Threat Radar's AI analysis · No CVSS score from NVD or the CNA

Thin evidence

One scorer or none

Exploitation evidence

Disclosed: evidence found.
CVE published 19 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 30 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.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), 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

AI-suggested

A patch has been applied to the Linux kernel that fixes this use-after-free bug by stopping and synchronously deleting the timer in vudc_remove(). Users should update to a Linux kernel version that includes this fix once available. No additional mitigations are indicated by the vendor advisory.

Description

A use-after-free vulnerability in the Linux kernel's usbip vudc_remove function due to a race condition has been fixed. The flaw involved a timer still pending or executing while its containing structure was freed, causing a potential memory safety issue. The fix involves stopping and synchronously deleting the timer during removal to prevent use-after-free.

Impact

The vulnerability could lead to a use-after-free condition in kernel memory, which may cause system instability or crashes. While no active exploitation in the wild is reported, the bug represents a memory safety flaw that could be leveraged for denial of service or potentially privilege escalation if combined with other vulnerabilities.

Summary

CVE-2026-63905 addresses a use-after-free bug in the Linux kernel's usbip virtual USB device controller (vudc) subsystem. The vulnerability arises from a race condition in the vudc_remove() function where the embedded timer_list within the vudc structure can be accessed after the structure has been freed. This occurs because the timer may still be pending or executing when vudc_remove() frees the vudc structure. The issue was confirmed by KASAN on an unpatched x86_64 QEMU guest with specific kernel configurations. The patch adds a call to v_stop_timer() in vudc_remove() to synchronously delete the timer, preventing the use-after-free condition.

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Exploitation evidence

What to do

Description

AI analysisMachine-generated, updated 30 Oct 2026, 15:36 UTC

Technical details

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