{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-52991", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-06-09T07:44:35.377Z", "datePublished": "2026-06-24T16:29:04.810Z", "dateUpdated": "2026-06-30T12:09:39.972Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-06-28T06:37:44.993Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsched/psi: fix race between file release and pressure write\n\nA potential race condition exists between pressure write and cgroup file\nrelease regarding the priv member of struct kernfs_open_file, which\ntriggers the uaf reported in [1].\n\nConsider the following scenario involving execution on two separate CPUs:\n\n CPU0\t\t\t\t\tCPU1\n ====\t\t\t\t\t====\n\t\t\t\t\tvfs_rmdir()\n\t\t\t\t\tkernfs_iop_rmdir()\n\t\t\t\t\tcgroup_rmdir()\n\t\t\t\t\tcgroup_kn_lock_live()\n\t\t\t\t\tcgroup_destroy_locked()\n\t\t\t\t\tcgroup_addrm_files()\n\t\t\t\t\tcgroup_rm_file()\n\t\t\t\t\tkernfs_remove_by_name()\n\t\t\t\t\tkernfs_remove_by_name_ns()\n vfs_write()\t\t\t\t__kernfs_remove()\n new_sync_write()\t\t\tkernfs_drain()\n kernfs_fop_write_iter()\t\tkernfs_drain_open_files()\n cgroup_file_write()\t\t\tkernfs_release_file()\n pressure_write()\t\t\tcgroup_file_release()\n ctx = of->priv;\n\t\t\t\t\tkfree(ctx);\n \t\t\t\t\tof->priv = NULL;\n\t\t\t\t\tcgroup_kn_unlock()\n cgroup_kn_lock_live()\n cgroup_get(cgrp)\n cgroup_kn_unlock()\n if (ctx->psi.trigger) // here, trigger uaf for ctx, that is of->priv\n\nThe cgroup_rmdir() is protected by the cgroup_mutex, it also safeguards\nthe memory deallocation of of->priv performed within cgroup_file_release().\nHowever, the operations involving of->priv executed within pressure_write()\nare not entirely covered by the protection of cgroup_mutex. Consequently,\nif the code in pressure_write(), specifically the section handling the\nctx variable executes after cgroup_file_release() has completed, a uaf\nvulnerability involving of->priv is triggered.\n\nTherefore, the issue can be resolved by extending the scope of the\ncgroup_mutex lock within pressure_write() to encompass all code paths\ninvolving of->priv, thereby properly synchronizing the race condition\noccurring between cgroup_file_release() and pressure_write().\n\nAnd, if an live kn lock can be successfully acquired while executing\nthe pressure write operation, it indicates that the cgroup deletion\nprocess has not yet reached its final stage; consequently, the priv\npointer within open_file cannot be NULL. Therefore, the operation to\nretrieve the ctx value must be moved to a point *after* the live kn\nlock has been successfully acquired.\n\nIn another situation, specifically after entering cgroup_kn_lock_live()\nbut before acquiring cgroup_mutex, there exists a different class of\nrace condition:\n\nCPU0: write memory.pressure CPU1: write cgroup.pressure=0\n===========================\t\t =============================\n\nkernfs_fop_write_iter()\n kernfs_get_active_of(of)\n pressure_write()\n cgroup_kn_lock_live(memory.pressure)\n cgroup_tryget(cgrp)\n kernfs_break_active_protection(kn)\n ... blocks on cgroup_mutex\n\n \t cgroup_pressure_write()\n \t cgroup_kn_lock_live(cgroup.pressure)\n \t cgroup_file_show(memory.pressure, false)\n \t kernfs_show(false)\n \t kernfs_drain_open_files()\n \t cgroup_file_release(of)\n \t kfree(ctx)\n \t of->priv = NULL\n \t cgroup_kn_unlock()\n\n ... acquires cgroup_mutex\n ctx = of->priv; // may now be NULL\n if (ctx->psi.trigger) // NULL dereference\n\nConsequently, there is a possibility that of->priv is NULL, the pressure\nwrite needs to check for this.\n\nNow that the scope of the cgroup_mutex has been expanded, the original\nexplicit cgroup_get/put operations are no longer necessary, this is\nbecause acquiring/releasing the live kn lock inherently executes a\ncgroup get/put operation.\n\n[1]\nBUG: KASAN: slab-use-after-free in pressure_write+0xa4/0x210 kernel/cgroup/cgroup.c:4011\nCall Trace:\n pressure_write+0xa4/0x210 kernel/cgroup/cgroup.c:4011\n cgroup_file_write+0x36f/0x790 kernel/cgroup/cgroup.c:43\n---truncated---"}], "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"}}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["kernel/cgroup/cgroup.c"], "versions": [{"version": "0e94682b73bfa6c44c98af7a26771c9c08c055d5", "lessThan": "03dc070fa0fc3cb4068693f468ccd5f8a7e58282", "status": "affected", "versionType": "git"}, {"version": "0e94682b73bfa6c44c98af7a26771c9c08c055d5", "lessThan": "d4352c0709bfd38c752fccbde7fd72a82ac78f23", "status": "affected", "versionType": "git"}, {"version": "0e94682b73bfa6c44c98af7a26771c9c08c055d5", "lessThan": "a5b98009f16d8a5fb4a8ff9a193f5735515c38fa", "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/cgroup/cgroup.c"], "versions": [{"version": "5.2", "status": "affected"}, {"version": "0", "lessThan": "5.2", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.33", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.0.10", "lessThanOrEqual": "7.0.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.1", "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": "5.2", "versionEndExcluding": "6.18.33"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.2", "versionEndExcluding": "7.0.10"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.2", "versionEndExcluding": "7.1"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/03dc070fa0fc3cb4068693f468ccd5f8a7e58282"}, {"url": "https://git.kernel.org/stable/c/d4352c0709bfd38c752fccbde7fd72a82ac78f23"}, {"url": "https://git.kernel.org/stable/c/a5b98009f16d8a5fb4a8ff9a193f5735515c38fa"}], "title": "sched/psi: fix race between file release and pressure write", "x_generator": {"engine": "bippy-1.2.0"}}, "adp": [{"affected": [{"cpes": ["cpe:/o:redhat:enterprise_linux:10"], "defaultStatus": "affected", "product": "Red Hat Enterprise Linux 10", "vendor": "Red Hat"}, {"cpes": ["cpe:/o:redhat:enterprise_linux:8"], "defaultStatus": "affected", "product": "Red Hat Enterprise Linux 8", "vendor": "Red Hat"}, {"cpes": ["cpe:/o:redhat:enterprise_linux:9"], "defaultStatus": "affected", "product": "Red Hat Enterprise Linux 9", "vendor": "Red Hat"}, {"cpes": ["cpe:/o:redhat:enterprise_linux:6"], "defaultStatus": "unaffected", "product": "Red Hat Enterprise Linux 6", "vendor": "Red Hat"}, {"cpes": ["cpe:/o:redhat:enterprise_linux:7"], "defaultStatus": "unaffected", "product": "Red Hat Enterprise Linux 7", "vendor": "Red Hat"}], "datePublic": "2026-06-24T00:00:00.000Z", "descriptions": [{"lang": "en", "value": "A flaw was found in the Linux kernel's Pressure Stall Information (PSI) subsystem. A race condition exists between the file release and pressure write operations, specifically concerning the `priv` member of `struct kernfs_open_file`. This can lead to a use-after-free vulnerability or a NULL dereference, potentially causing system instability or a denial of service. The issue arises when the `priv` member is deallocated during a cgroup file release while a pressure write operation attempts to access it, or when it becomes NULL before being accessed."}], "metrics": [{"other": {"content": {"namespace": "https://access.redhat.com/security/updates/classification/", "value": "Important"}, "type": "Red Hat severity rating"}}, {"cvssV3_1": {"attackComplexity": "HIGH", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "format": "CVSS"}], "problemTypes": [{"descriptions": [{"cweId": "CWE-367", "description": "Time-of-check Time-of-use (TOCTOU) Race Condition", "lang": "en", "type": "CWE"}]}], "references": [{"tags": ["vdb-entry", "x_refsource_REDHAT"], "url": "https://access.redhat.com/security/cve/CVE-2026-52991"}, {"name": "RHBZ#2492403", "tags": ["issue-tracking", "x_refsource_REDHAT"], "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2492403"}, {"tags": ["x_sadp-csaf-vex"], "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-52991.json"}], "timeline": [{"lang": "en", "time": "2026-06-24T00:00:00.000Z", "value": "Reported to Red Hat."}, {"lang": "en", "time": "2026-06-24T00:00:00.000Z", "value": "Made public."}], "title": "kernel: sched/psi: fix race between file release and pressure write", "x_adpType": "supplier", "x_generator": {"engine": "sadp-cli 1.0.0"}, "providerMetadata": {"orgId": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c", "shortName": "redhat-SADP", "dateUpdated": "2026-06-30T12:09:39.972Z"}}]}}

{}

{}

{"bugzilla": {"description": "kernel: sched/psi: fix race between file release and pressure write", "id": "2492403", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2492403"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.0", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H", "status": "draft"}, "cwe": "CWE-367", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nsched/psi: fix race between file release and pressure write\nA potential race condition exists between pressure write and cgroup file\nrelease regarding the priv member of struct kernfs_open_file, which\ntriggers the uaf reported in [1].\nConsider the following scenario involving execution on two separate CPUs:\nCPU0CPU1\n========\nvfs_rmdir()\nkernfs_iop_rmdir()\ncgroup_rmdir()\ncgroup_kn_lock_live()\ncgroup_destroy_locked()\ncgroup_addrm_files()\ncgroup_rm_file()\nkernfs_remove_by_name()\nkernfs_remove_by_name_ns()\nvfs_write()__kernfs_remove()\nnew_sync_write()kernfs_drain()\nkernfs_fop_write_iter()kernfs_drain_open_files()\ncgroup_file_write()kernfs_release_file()\npressure_write()cgroup_file_release()\nctx = of->priv;\nkfree(ctx);\nof->priv = NULL;\ncgroup_kn_unlock()\ncgroup_kn_lock_live()\ncgroup_get(cgrp)\ncgroup_kn_unlock()\nif (ctx->psi.trigger) // here, trigger uaf for ctx, that is of->priv\nThe cgroup_rmdir() is protected by the cgroup_mutex, it also safeguards\nthe memory deallocation of of->priv performed within cgroup_file_release().\nHowever, the operations involving of->priv executed within pressure_write()\nare not entirely covered by the protection of cgroup_mutex. Consequently,\nif the code in pressure_write(), specifically the section handling the\nctx variable executes after cgroup_file_release() has completed, a uaf\nvulnerability involving of->priv is triggered.\nTherefore, the issue can be resolved by extending the scope of the\ncgroup_mutex lock within pressure_write() to encompass all code paths\ninvolving of->priv, thereby properly synchronizing the race condition\noccurring between cgroup_file_release() and pressure_write().\nAnd, if an live kn lock can be successfully acquired while executing\nthe pressure write operation, it indicates that the cgroup deletion\nprocess has not yet reached its final stage; consequently, the priv\npointer within open_file cannot be NULL. Therefore, the operation to\nretrieve the ctx value must be moved to a point *after* the live kn\nlock has been successfully acquired.\nIn another situation, specifically after entering cgroup_kn_lock_live()\nbut before acquiring cgroup_mutex, there exists a different class of\nrace condition:\nCPU0: write memory.pressure CPU1: write cgroup.pressure=0\n=========================== =============================\nkernfs_fop_write_iter()\nkernfs_get_active_of(of)\npressure_write()\ncgroup_kn_lock_live(memory.pressure)\ncgroup_tryget(cgrp)\nkernfs_break_active_protection(kn)\n... blocks on cgroup_mutex\ncgroup_pressure_write()\ncgroup_kn_lock_live(cgroup.pressure)\ncgroup_file_show(memory.pressure, false)\nkernfs_show(false)\nkernfs_drain_open_files()\ncgroup_file_release(of)\nkfree(ctx)\nof->priv = NULL\ncgroup_kn_unlock()\n... acquires cgroup_mutex\nctx = of->priv; // may now be NULL\nif (ctx->psi.trigger) // NULL dereference\nConsequently, there is a possibility that of->priv is NULL, the pressure\nwrite needs to check for this.\nNow that the scope of the cgroup_mutex has been expanded, the original\nexplicit cgroup_get/put operations are no longer necessary, this is\nbecause acquiring/releasing the live kn lock inherently executes a\ncgroup get/put operation.\n[1]\nBUG: KASAN: slab-use-after-free in pressure_write+0xa4/0x210 kernel/cgroup/cgroup.c:4011\nCall Trace:\npressure_write+0xa4/0x210 kernel/cgroup/cgroup.c:4011\ncgroup_file_write+0x36f/0x790 kernel/cgroup/cgroup.c:43\n---truncated---", "A flaw was found in the Linux kernel's Pressure Stall Information (PSI) subsystem. A race condition exists between the file release and pressure write operations, specifically concerning the `priv` member of `struct kernfs_open_file`. This can lead to a use-after-free vulnerability or a NULL dereference, potentially causing system instability or a denial of service. The issue arises when the `priv` member is deallocated during a cgroup file release while a pressure write operation attempts to access it, or when it becomes NULL before being accessed."], "name": "CVE-2026-52991", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-06-24T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-52991\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-52991\nhttps://lore.kernel.org/linux-cve-announce/2026062444-CVE-2026-52991-18fe@gregkh/T"], "threat_severity": "Important"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[0e94682b73bfa6c44c98af7a26771c9c08c055d5,03dc070fa0fc3cb4068693f468ccd5f8a7e58282)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[0e94682b73bfa6c44c98af7a26771c9c08c055d5,d4352c0709bfd38c752fccbde7fd72a82ac78f23)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[0e94682b73bfa6c44c98af7a26771c9c08c055d5,a5b98009f16d8a5fb4a8ff9a193f5735515c38fa)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "5.2"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[0,5.2)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.33,6.18.*]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.0.10,7.0.*]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.1,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-06-24T21:00:11.772834+00:00", "updated": "2026-06-28T15:15:05.994988+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}