memcg: use round-robin victim selection in refill_stock_CVE-2026-53162

{
    "lastseen": "",
    "description": "In the Linux kernel, the following vulnerability has been resolved:\n\nmemcg: use round-robin victim selection in refill_stock\n\nHarry Yoo reported that get_random_u32_below() is not safe to call in the\nnmi context and memcg charge draining can happen in nmi context.\n\nMore specifically get_random_u32_below() is neither reentrant- nor\nNMI-safe: it acquires a per-cpu local_lock via local_lock_irqsave() on the\nbatched_entropy_u32 state.  An NMI that lands on a CPU mid-update of the\nChaCha batch state and recurses into the random subsystem would corrupt\nthat state.  The memcg_stock local_trylock prevents re-entry on the percpu\nstock itself, but cannot protect an unrelated subsystem's per-cpu lock.\n\nReplace the random pick with a per-cpu round-robin counter stored in\nmemcg_stock_pcp and serialized by the same local_trylock that already\nguards cached[] and nr_pages[].  No atomics, no random calls, no extra\nlocks needed.",
    "published": "2026-06-25T08:38:43.453Z",
    "modified": "2026-06-28T06:39:38.906Z",
    "type": "cve",
    "title": "memcg: use round-robin victim selection in refill_stock",
    "source": "Linux",
    "references": "https://git.kernel.org/stable/c/89bd8215e25aa6999cc51696da418e0d422bc5e0\nhttps://git.kernel.org/stable/c/00731bd7e18f182a32ca54d6b176eaa470b51ed7\nhttps://git.kernel.org/stable/c/c0cafe24d3f6534294c4b2bc2d47734ff7cbd313",
    "id": "CVE-2026-53162",
    "bulletinFamily": "",
    "cwe": null,
    "cvelist": null,
    "sourceData": "Linux Linux f735eebe55f8f61758fe014bd0b02ab50b059e4d\nLinux Linux f735eebe55f8f61758fe014bd0b02ab50b059e4d\nLinux Linux f735eebe55f8f61758fe014bd0b02ab50b059e4d\nLinux Linux 6.16",
    "sourceHref": "",
    "cvss": {
        "score": 7.8,
        "severity": "HIGH",
        "vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
            "attackVector": "",
            "attackComplexity": "",
            "privilegesRequired": "",
            "userInteraction": "",
            "scope": "",
            "confidentialityImpact": "",
            "integrityImpact": "",
            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "Linux",
    "version": "f735eebe55f8f61758fe014bd0b02ab50b059e4d",
    "vendor": "Linux",
    "ai_description": "",
    "ai_severity": "",
    "ai_vendor": "",
    "ai_product": "",
    "ai_version": "",
    "ai_score": 0
}