GHSA-426X-JC5H-FMGG
Vulnerability from github – Published: 2026-04-24 15:32 – Updated: 2026-06-01 18:31In 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.
{
"affected": [],
"aliases": [
"CVE-2026-31602"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-04-24T15:16:39Z",
"severity": "HIGH"
},
"details": "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.",
"id": "GHSA-426x-jc5h-fmgg",
"modified": "2026-06-01T18:31:27Z",
"published": "2026-04-24T15:32:35Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-31602"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/2b4331c08c0b385598b4d8ccd71e93ab3f4b2578"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/365c36e1a126c6aa1aecedd3a351bcabc66f0c29"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3fd0685d7fef68c2d8a04876bcf9eaa0724ad6a5"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/452894005b4abe141b11fe01e7bfe152e6d3860f"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ad9011a795407093dcf507f6e5da1828987b4b47"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/b7f5ecd13cce8c2f8fa5a84c9aab65997142577e"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/c5908160e17cb56e1f61fbaee08adc21083f4933"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/de8016fb0904d68ac886e375069535996baa42ee"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/e9418da50d9e5c496c22fe392e4ad74c038a94eb"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
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