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vuln-cve/data/2026/23xxx/CVE-2026-23248.json
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{
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"cveMetadata": {
"cveId": "CVE-2026-23248",
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"state": "PUBLISHED",
"assignerShortName": "Linux",
"dateReserved": "2026-01-13T15:37:45.989Z",
"datePublished": "2026-03-18T10:05:10.070Z",
"dateUpdated": "2026-10-19T18:35:40.258Z"
},
"containers": {
"cna": {
"providerMetadata": {
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux",
"dateUpdated": "2026-08-05T12:20:56.308Z"
},
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nperf/core: Fix refcount bug and potential UAF in perf_mmap\n\nSyzkaller reported a refcount_t: addition on 0; use-after-free warning\nin perf_mmap.\n\nThe issue is caused by a race condition between a failing mmap() setup\nand a concurrent mmap() on a dependent event (e.g., using output\nredirection).\n\nIn perf_mmap(), the ring_buffer (rb) is allocated and assigned to\nevent->rb with the mmap_mutex held. The mutex is then released to\nperform map_range().\n\nIf map_range() fails, perf_mmap_close() is called to clean up.\nHowever, since the mutex was dropped, another thread attaching to\nthis event (via inherited events or output redirection) can acquire\nthe mutex, observe the valid event->rb pointer, and attempt to\nincrement its reference count. If the cleanup path has already\ndropped the reference count to zero, this results in a\nuse-after-free or refcount saturation warning.\n\nFix this by extending the scope of mmap_mutex to cover the\nmap_range() call. This ensures that the ring buffer initialization\nand mapping (or cleanup on failure) happens atomically effectively,\npreventing other threads from accessing a half-initialized or\ndying ring buffer."
}
],
"metrics": [
{
"cvssV3_1": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"baseScore": 7.8,
"baseSeverity": "HIGH"
},
"scenarios": [
{
"lang": "en",
"value": "AV:L - The vulnerability is triggered via the perf_event_open() syscall followed by mmap() on the resulting file descriptor, requiring local system access.\nAC:L - The attacker controls both sides of the race by spawning two threads that concurrently mmap() the same perf event fd. Per CVSS guidance, attacker-controlled races are AC:L.\nPR:L - Unprivileged local users can use perf_event_open() with exclude_kernel=1 and per-task events (cpu=-1) even with the default perf_event_paranoid=2, then mmap() the resulting fd to trigger the race.\nUI:N - No user interaction is needed; the attacker creates the perf event and triggers the race entirely on their own.\nS:U - This is a standard kernel use-after-free for privilege escalation within the same security authority; no VM escape or sandbox boundary crossing occurs.\nC:H - The UAF on the perf_buffer heap object allows the attacker to spray controlled data into the freed slab, enabling arbitrary kernel memory reads through the buffer's data page pointers and user_page.\nI:H - The freed perf_buffer contains function pointers (free_aux) and is accessed through multiple code paths, enabling heap spraying for arbitrary write primitives and control flow hijacking.\nA:H - The use-after-free reliably causes kernel crashes (refcount saturation warnings, oops, or panic) when the freed ring buffer is accessed."
}
]
}
],
"affected": [
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "unaffected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"kernel/events/core.c"
],
"versions": [
{
"version": "b709eb872e19a19607bbb6d2975bc264d59735cf",
"lessThan": "c27dea9f50ed525facb62ef647dddc4722456e07",
"status": "affected",
"versionType": "git"
},
{
"version": "b709eb872e19a19607bbb6d2975bc264d59735cf",
"lessThan": "ac7ecb65af170a7fc193e7bd8be15dac84ec6a56",
"status": "affected",
"versionType": "git"
},
{
"version": "b709eb872e19a19607bbb6d2975bc264d59735cf",
"lessThan": "77de62ad3de3967818c3dbe656b7336ebee461d2",
"status": "affected",
"versionType": "git"
}
]
},
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "affected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"kernel/events/core.c"
],
"versions": [
{
"version": "6.14",
"status": "affected"
},
{
"version": "0",
"lessThan": "6.14",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "6.18.17",
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "6.19.7",
"lessThanOrEqual": "6.19.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "7.0",
"lessThanOrEqual": "*",
"status": "unaffected",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"operator": "OR",
"negate": false,
"cpeMatch": [
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "6.14",
"versionEndExcluding": "6.18.17"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "6.14",
"versionEndExcluding": "6.19.7"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "6.14",
"versionEndExcluding": "7.0"
}
]
}
]
}
],
"references": [
{
"url": "https://git.kernel.org/stable/c/c27dea9f50ed525facb62ef647dddc4722456e07"
},
{
"url": "https://git.kernel.org/stable/c/ac7ecb65af170a7fc193e7bd8be15dac84ec6a56"
},
{
"url": "https://git.kernel.org/stable/c/77de62ad3de3967818c3dbe656b7336ebee461d2"
}
],
"title": "perf/core: Fix refcount bug and potential UAF in perf_mmap",
"x_generator": {
"engine": "bippy-1.2.0"
}
},
"adp": [
{
"metrics": [
{
"other": {
"type": "ssvc",
"content": {
"id": "CVE-2026-23248",
"role": "CISA Coordinator",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "no"
},
{
"Technical Impact": "total"
}
],
"version": "2.0.3",
"timestamp": "2026-10-16T15:06:58.307161Z"
}
}
}
],
"problemTypes": [
{
"descriptions": [
{
"lang": "en",
"type": "CWE",
"cweId": "CWE-362",
"description": "CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')"
}
]
}
],
"title": "CISA ADP Vulnrichment",
"providerMetadata": {
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP",
"dateUpdated": "2026-10-19T18:35:40.258Z"
}
}
]
}
}