GHSA-XCG5-9P3P-FGRJ
Vulnerability from github – Published: 2026-02-14 18:30 – Updated: 2026-03-19 18:31In the Linux kernel, the following vulnerability has been resolved:
cgroup/dmem: avoid pool UAF
An UAF issue was observed:
BUG: KASAN: slab-use-after-free in page_counter_uncharge+0x65/0x150 Write of size 8 at addr ffff888106715440 by task insmod/527
CPU: 4 UID: 0 PID: 527 Comm: insmod 6.19.0-rc7-next-20260129+ #11 Tainted: [O]=OOT_MODULE Call Trace: dump_stack_lvl+0x82/0xd0 kasan_report+0xca/0x100 kasan_check_range+0x39/0x1c0 page_counter_uncharge+0x65/0x150 dmem_cgroup_uncharge+0x1f/0x260
Allocated by task 527:
Freed by task 0:
The buggy address belongs to the object at ffff888106715400 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 64 bytes inside of freed 512-byte region [ffff888106715400, ffff888106715600)
The buggy address belongs to the physical page:
Memory state around the buggy address: ffff888106715300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888106715380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888106715400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888106715480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888106715500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
The issue occurs because a pool can still be held by a caller after its associated memory region is unregistered. The current implementation frees the pool even if users still hold references to it (e.g., before uncharge operations complete).
This patch adds a reference counter to each pool, ensuring that a pool is only freed when its reference count drops to zero.
{
"affected": [],
"aliases": [
"CVE-2026-23195"
],
"database_specific": {
"cwe_ids": [
"CWE-416"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-02-14T17:15:57Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\ncgroup/dmem: avoid pool UAF\n\nAn UAF issue was observed:\n\nBUG: KASAN: slab-use-after-free in page_counter_uncharge+0x65/0x150\nWrite of size 8 at addr ffff888106715440 by task insmod/527\n\nCPU: 4 UID: 0 PID: 527 Comm: insmod 6.19.0-rc7-next-20260129+ #11\nTainted: [O]=OOT_MODULE\nCall Trace:\n\u003cTASK\u003e\ndump_stack_lvl+0x82/0xd0\nkasan_report+0xca/0x100\nkasan_check_range+0x39/0x1c0\npage_counter_uncharge+0x65/0x150\ndmem_cgroup_uncharge+0x1f/0x260\n\nAllocated by task 527:\n\nFreed by task 0:\n\nThe buggy address belongs to the object at ffff888106715400\nwhich belongs to the cache kmalloc-512 of size 512\nThe buggy address is located 64 bytes inside of\nfreed 512-byte region [ffff888106715400, ffff888106715600)\n\nThe buggy address belongs to the physical page:\n\nMemory state around the buggy address:\nffff888106715300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc\nffff888106715380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc\n\u003effff888106715400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb\n\t\t\t\t ^\nffff888106715480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb\nffff888106715500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb\n\nThe issue occurs because a pool can still be held by a caller after its\nassociated memory region is unregistered. The current implementation frees\nthe pool even if users still hold references to it (e.g., before uncharge\noperations complete).\n\nThis patch adds a reference counter to each pool, ensuring that a pool is\nonly freed when its reference count drops to zero.",
"id": "GHSA-xcg5-9p3p-fgrj",
"modified": "2026-03-19T18:31:14Z",
"published": "2026-02-14T18:30:16Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-23195"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/99a2ef500906138ba58093b9893972a5c303c734"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/d3081353acaa6a638dcf75726066ea556a2de8d5"
}
],
"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"
}
]
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
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- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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