CVE-2026-31602

Kernel crash via ctxfi page-table overflow

Published Apr 24, 2026 · Updated Apr 24, 2026

Out-of-bounds access in Linux Kernel ALSA ctxfi allows local users to crash the kernel by preparing aggregate playback memory above 2 MiB. ct_vm_map() always writes PTEs through vm->ptp[0].area even after CT_PTP_NUM was raised to four, so allocations beyond the first 512-entry page table access unallocated space. Reachability requires an AMD64 system using the snd_ctxfi driver for CT20K2 hardware and enough aggregate playback allocation to cross the 2 MiB boundary; the resulting page fault produces a kernel oops.

CVSS severity7.8
High
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds access in Linux Kernel ALSA ctxfi allows local users to crash the kernel by preparing aggregate playback memory above 2 MiB. ct_vm_map() always writes PTEs through vm->ptp[0].area even after CT_PTP_NUM was raised to four, so allocations beyond the first 512-entry page table access unallocated space. Reachability requires an AMD64 system using the snd_ctxfi driver for CT20K2 hardware and enough aggregate playback allocation to cross the 2 MiB boundary; the resulting page fault produces a kernel oops.

The record

CVE
CVE-2026-31602
Published
Apr 24, 2026
Updated
Apr 24, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 24, 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.

  1. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <365c36e1a126c6aa1aecedd3a351bcabc66f0c29
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <3fd0685d7fef68c2d8a04876bcf9eaa0724ad6a5
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ad9011a795407093dcf507f6e5da1828987b4b47
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <b7f5ecd13cce8c2f8fa5a84c9aab65997142577e

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <365c36e1a126c6aa1aecedd3a351bcabc66f0c29; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <3fd0685d7fef68c2d8a04876bcf9eaa0724ad6a5; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ad9011a795407093dcf507f6e5da1828987b4b47; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <b7f5ecd13cce8c2f8fa5a84c9aab65997142577e

Published CVSS scores

7.8kernel.orgCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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