CVE-2026-31602 (GCVE-0-2026-31602)

Vulnerability from cvelistv5 – Published: 2026-04-24 14:42 – Updated: 2026-04-24 14:42
VLAI?
Title
ALSA: ctxfi: Limit PTP to a single page
Summary
In the Linux kernel, the following vulnerability has been resolved: ALSA: ctxfi: Limit PTP to a single page Commit 391e69143d0a increased CT_PTP_NUM from 1 to 4 to support 256 playback streams, but the additional pages are not used by the card correctly. The CT20K2 hardware already has multiple VMEM_PTPAL registers, but using them separately would require refactoring the entire virtual memory allocation logic. ct_vm_map() always uses PTEs in vm->ptp[0].area regardless of CT_PTP_NUM. On AMD64 systems, a single PTP covers 512 PTEs (2M). When aggregate memory allocations exceed this limit, ct_vm_map() tries to access beyond the allocated space and causes a page fault: BUG: unable to handle page fault for address: ffffd4ae8a10a000 Oops: Oops: 0002 [#1] SMP PTI RIP: 0010:ct_vm_map+0x17c/0x280 [snd_ctxfi] Call Trace: atc_pcm_playback_prepare+0x225/0x3b0 ct_pcm_playback_prepare+0x38/0x60 snd_pcm_do_prepare+0x2f/0x50 snd_pcm_action_single+0x36/0x90 snd_pcm_action_nonatomic+0xbf/0xd0 snd_pcm_ioctl+0x28/0x40 __x64_sys_ioctl+0x97/0xe0 do_syscall_64+0x81/0x610 entry_SYSCALL_64_after_hwframe+0x76/0x7e Revert CT_PTP_NUM to 1. The 256 SRC_RESOURCE_NUM and playback_count remain unchanged.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 365c36e1a126c6aa1aecedd3a351bcabc66f0c29 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 3fd0685d7fef68c2d8a04876bcf9eaa0724ad6a5 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < b7f5ecd13cce8c2f8fa5a84c9aab65997142577e (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < ad9011a795407093dcf507f6e5da1828987b4b47 (git)
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    Linux Linux Unaffected: 6.12.83 , ≤ 6.12.* (semver)
Unaffected: 6.18.24 , ≤ 6.18.* (semver)
Unaffected: 6.19.14 , ≤ 6.19.* (semver)
Unaffected: 7.0.1 , ≤ 7.0.* (semver)
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          "product": "Linux",
          "programFiles": [
            "sound/pci/ctxfi/ctvmem.h"
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          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: ctxfi: Limit PTP to a single page\n\nCommit 391e69143d0a increased CT_PTP_NUM from 1 to 4 to support 256\nplayback streams, but the additional pages are not used by the card\ncorrectly. The CT20K2 hardware already has multiple VMEM_PTPAL\nregisters, but using them separately would require refactoring the\nentire virtual memory allocation logic.\n\nct_vm_map() always uses PTEs in vm-\u003eptp[0].area regardless of\nCT_PTP_NUM. On AMD64 systems, a single PTP covers 512 PTEs (2M). When\naggregate memory allocations exceed this limit, ct_vm_map() tries to\naccess beyond the allocated space and causes a page fault:\n\n  BUG: unable to handle page fault for address: ffffd4ae8a10a000\n  Oops: Oops: 0002 [#1] SMP PTI\n  RIP: 0010:ct_vm_map+0x17c/0x280 [snd_ctxfi]\n  Call Trace:\n  atc_pcm_playback_prepare+0x225/0x3b0\n  ct_pcm_playback_prepare+0x38/0x60\n  snd_pcm_do_prepare+0x2f/0x50\n  snd_pcm_action_single+0x36/0x90\n  snd_pcm_action_nonatomic+0xbf/0xd0\n  snd_pcm_ioctl+0x28/0x40\n  __x64_sys_ioctl+0x97/0xe0\n  do_syscall_64+0x81/0x610\n  entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\nRevert CT_PTP_NUM to 1. The 256 SRC_RESOURCE_NUM and playback_count\nremain unchanged."
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        "dateUpdated": "2026-04-24T14:42:25.935Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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        },
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      ],
      "title": "ALSA: ctxfi: Limit PTP to a single page",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-31602",
    "datePublished": "2026-04-24T14:42:25.935Z",
    "dateReserved": "2026-03-09T15:48:24.121Z",
    "dateUpdated": "2026-04-24T14:42:25.935Z",
    "state": "PUBLISHED"
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      "date": "2026-04-25",
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  }
}


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  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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Detection rules are retrieved from Rulezet.