Kernel memory corruption via unflushed anchored URBs
Published May 1, 2026 · Updated May 1, 2026
Use-after-free in Linux Kernel 4.19 and later allows local users to corrupt kernel memory by closing a USBTMC file with pending URBs. usbtmc_release frees per-file state without first calling usbtmc_draw_down, so an anchored URB can complete through the HCD giveback path and access that released state. A local low-privilege user needs access to a USBTMC device; the public reproducer demonstrates a kernel memory write and crash, but not code execution.
Summary
What happened
Use-after-free in Linux Kernel 4.19 and later allows local users to corrupt kernel memory by closing a USBTMC file with pending URBs. usbtmc_release frees per-file state without first calling usbtmc_draw_down, so an anchored URB can complete through the HCD giveback path and access that released state. A local low-privilege user needs access to a USBTMC device; the public reproducer demonstrates a kernel memory write and crash, but not code execution.
The record
- CVE
- CVE-2026-31758
- Published
- May 1, 2026
- Updated
- May 1, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- CWE-416, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- May 1, 2026CVE publishedPublication date reported by the CVE source.
- May 1, 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.
- Affected versionversion=4.19
- Affected versionversion=4f3c8d6eddc272b386464524235440a418ed2029 <7fa8f61bab3fb75b5deba8a0f3abb74dc5068d9f
- Affected versionversion=4f3c8d6eddc272b386464524235440a418ed2029 <8a768552f7a8276fb9e01d49773d2094ace7c8f1
- Affected versionversion=4f3c8d6eddc272b386464524235440a418ed2029 <959ef329071136e4335b54822fe2f607659b4569
- Affected versionversion=4f3c8d6eddc272b386464524235440a418ed2029 <95e09b07e50290254b28b8395509473104518f8c
- Affected versionversion=4f3c8d6eddc272b386464524235440a418ed2029 <977b632db51d231dec0bc571089a5c2402674139
- Affected versionversion=4f3c8d6eddc272b386464524235440a418ed2029 <d13318dec0c1e0e2ac16f8ecbd522db14cea4bb1
- Affected versionversion=4f3c8d6eddc272b386464524235440a418ed2029 <d40198de50232e04c14c6e2092e896766c95ea48
- Affected versionversion=4f3c8d6eddc272b386464524235440a418ed2029 <e189d443767f7cd390c52f2e122e1fc41c7562d6
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Public exploit references
- syzbot C reproducer for usb_anchor_suspend_wakeups use-after-freeproof of concept · demonstrated
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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