CVE-2026-45895

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-45895", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-05-13T15:03:33.083Z", "datePublished": "2026-05-27T12:17:05.666Z", "dateUpdated": "2026-05-27T12:17:05.666Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-05-27T12:17:05.666Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nquota: fix livelock between quotactl and freeze_super\n\nWhen a filesystem is frozen, quotactl_block() enters a retry loop\nwaiting for the filesystem to thaw. It acquires s_umount, checks the\nfreeze state, drops s_umount and uses sb_start_write() - sb_end_write()\npair to wait for the unfreeze.\n\nHowever, this retry loop can trigger a livelock issue, specifically on\nkernels with preemption disabled.\n\nThe mechanism is as follows:\n1. freeze_super() sets SB_FREEZE_WRITE and calls sb_wait_write().\n2. sb_wait_write() calls percpu_down_write(), which initiates\n synchronize_rcu().\n3. Simultaneously, quotactl_block() spins in its retry loop, immediately\n executing the sb_start_write() - sb_end_write() pair.\n4. Because the kernel is non-preemptible and the loop contains no\n scheduling points, quotactl_block() never yields the CPU. This\n prevents that CPU from reaching an RCU quiescent state.\n5. synchronize_rcu() in the freezer thread waits indefinitely for the\n quotactl_block() CPU to report a quiescent state.\n6. quotactl_block() spins indefinitely waiting for the freezer to\n advance, which it cannot do as it is blocked on the RCU sync.\n\nThis results in a hang of the freezer process and 100% CPU usage by the\nquota process.\n\nWhile this can occur intermittently on multi-core systems, it is\nreliably reproducing on a node with the following script, running both\nthe freezer and the quota toggle on the same CPU:\n\n # mkfs.ext4 -O quota /dev/sda 2g && mkdir a_mount\n # mount /dev/sda -o quota,usrquota,grpquota a_mount\n # taskset -c 3 bash -c \"while true; do xfs_freeze -f a_mount; \\\n xfs_freeze -u a_mount; done\" &\n # taskset -c 3 bash -c \"while true; do quotaon a_mount; \\\n quotaoff a_mount; done\" &\n\nAdding cond_resched() to the retry loop fixes the issue. It acts as an\nRCU quiescent state, allowing synchronize_rcu() in percpu_down_write()\nto complete."}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/quota/quota.c"], "versions": [{"version": "576215cffdefc1f0ceebffd87abb390926e6b037", "lessThan": "37ccd48cf35f3c8b9f2ea961a7b486b91eb71a82", "status": "affected", "versionType": "git"}, {"version": "576215cffdefc1f0ceebffd87abb390926e6b037", "lessThan": "414259caf81a397563fc9baca9c0ef856c4a97cf", "status": "affected", "versionType": "git"}, {"version": "576215cffdefc1f0ceebffd87abb390926e6b037", "lessThan": "02bb1500f1479750e6557c8044f6a2d7e9d30c12", "status": "affected", "versionType": "git"}, {"version": "576215cffdefc1f0ceebffd87abb390926e6b037", "lessThan": "53b2314b26b6640a3657cc924de63a1a8f26ac4d", "status": "affected", "versionType": "git"}, {"version": "576215cffdefc1f0ceebffd87abb390926e6b037", "lessThan": "77449e453dfc006ad738dec55374c4cbc056fd39", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/quota/quota.c"], "versions": [{"version": "6.5", "status": "affected"}, {"version": "0", "lessThan": "6.5", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.128", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.75", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.14", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.19.4", "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": "6.5", "versionEndExcluding": "6.6.128"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.5", "versionEndExcluding": "6.12.75"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.5", "versionEndExcluding": "6.18.14"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.5", "versionEndExcluding": "6.19.4"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.5", "versionEndExcluding": "7.0"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/37ccd48cf35f3c8b9f2ea961a7b486b91eb71a82"}, {"url": "https://git.kernel.org/stable/c/414259caf81a397563fc9baca9c0ef856c4a97cf"}, {"url": "https://git.kernel.org/stable/c/02bb1500f1479750e6557c8044f6a2d7e9d30c12"}, {"url": "https://git.kernel.org/stable/c/53b2314b26b6640a3657cc924de63a1a8f26ac4d"}, {"url": "https://git.kernel.org/stable/c/77449e453dfc006ad738dec55374c4cbc056fd39"}], "title": "quota: fix livelock between quotactl and freeze_super", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["fs/quota/quota.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "37ccd48cf35f3c8b9f2ea961a7b486b91eb71a82", "status": "affected", "version": "576215cffdefc1f0ceebffd87abb390926e6b037", "versionType": "git"}, {"lessThan": "414259caf81a397563fc9baca9c0ef856c4a97cf", "status": "affected", "version": "576215cffdefc1f0ceebffd87abb390926e6b037", "versionType": "git"}, {"lessThan": "02bb1500f1479750e6557c8044f6a2d7e9d30c12", "status": "affected", "version": "576215cffdefc1f0ceebffd87abb390926e6b037", "versionType": "git"}, {"lessThan": "53b2314b26b6640a3657cc924de63a1a8f26ac4d", "status": "affected", "version": "576215cffdefc1f0ceebffd87abb390926e6b037", "versionType": "git"}, {"lessThan": "77449e453dfc006ad738dec55374c4cbc056fd39", "status": "affected", "version": "576215cffdefc1f0ceebffd87abb390926e6b037", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["fs/quota/quota.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "6.5"}, {"lessThan": "6.5", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.6.*", "status": "unaffected", "version": "6.6.128", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.75", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.14", "versionType": "semver"}, {"lessThanOrEqual": "6.19.*", "status": "unaffected", "version": "6.19.4", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.0", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "A502C6C1-0CFB-4C9B-8A24-C76507206FA7", "versionEndExcluding": "6.6.128", "versionStartIncluding": "6.5", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "BCE16369-98ED-41CF-8995-DFDC10B288D2", "versionEndExcluding": "6.12.75", "versionStartIncluding": "6.7", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "BF463CB7-1F58-4607-B847-77ED23E4B9B7", "versionEndExcluding": "6.18.14", "versionStartIncluding": "6.13", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "672A3E79-EC03-479D-8503-361DFBDC8092", "versionEndExcluding": "6.19.4", "versionStartIncluding": "6.19", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nquota: fix livelock between quotactl and freeze_super\n\nWhen a filesystem is frozen, quotactl_block() enters a retry loop\nwaiting for the filesystem to thaw. It acquires s_umount, checks the\nfreeze state, drops s_umount and uses sb_start_write() - sb_end_write()\npair to wait for the unfreeze.\n\nHowever, this retry loop can trigger a livelock issue, specifically on\nkernels with preemption disabled.\n\nThe mechanism is as follows:\n1. freeze_super() sets SB_FREEZE_WRITE and calls sb_wait_write().\n2. sb_wait_write() calls percpu_down_write(), which initiates\n synchronize_rcu().\n3. Simultaneously, quotactl_block() spins in its retry loop, immediately\n executing the sb_start_write() - sb_end_write() pair.\n4. Because the kernel is non-preemptible and the loop contains no\n scheduling points, quotactl_block() never yields the CPU. This\n prevents that CPU from reaching an RCU quiescent state.\n5. synchronize_rcu() in the freezer thread waits indefinitely for the\n quotactl_block() CPU to report a quiescent state.\n6. quotactl_block() spins indefinitely waiting for the freezer to\n advance, which it cannot do as it is blocked on the RCU sync.\n\nThis results in a hang of the freezer process and 100% CPU usage by the\nquota process.\n\nWhile this can occur intermittently on multi-core systems, it is\nreliably reproducing on a node with the following script, running both\nthe freezer and the quota toggle on the same CPU:\n\n # mkfs.ext4 -O quota /dev/sda 2g && mkdir a_mount\n # mount /dev/sda -o quota,usrquota,grpquota a_mount\n # taskset -c 3 bash -c \"while true; do xfs_freeze -f a_mount; \\\n xfs_freeze -u a_mount; done\" &\n # taskset -c 3 bash -c \"while true; do quotaon a_mount; \\\n quotaoff a_mount; done\" &\n\nAdding cond_resched() to the retry loop fixes the issue. It acts as an\nRCU quiescent state, allowing synchronize_rcu() in percpu_down_write()\nto complete."}], "id": "CVE-2026-45895", "lastModified": "2026-06-25T21:09:58.390", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 5.5, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 3.6, "source": "nvd@nist.gov", "type": "Primary"}]}, "published": "2026-05-27T14:17:03.733", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/02bb1500f1479750e6557c8044f6a2d7e9d30c12"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/37ccd48cf35f3c8b9f2ea961a7b486b91eb71a82"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/414259caf81a397563fc9baca9c0ef856c4a97cf"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/53b2314b26b6640a3657cc924de63a1a8f26ac4d"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/77449e453dfc006ad738dec55374c4cbc056fd39"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "NVD-CWE-noinfo"}], "source": "nvd@nist.gov", "type": "Primary"}]}

{"bugzilla": {"description": "kernel: quota: fix livelock between quotactl and freeze_super", "id": "2482169", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2482169"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.5", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-835", "details": ["A flaw was found in the Linux kernel. A local attacker could exploit a livelock condition between the `quotactl` and `freeze_super` operations. This occurs when a filesystem is frozen and the `quotactl_block()` function enters a retry loop, preventing the system from reaching an RCU (Read-Copy Update) quiescent state. This can lead to a system hang of the freezer process and 100% CPU utilization by the quota process, resulting in a Denial of Service (DoS)."], "name": "CVE-2026-45895", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Out of support scope", "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": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-05-27T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-45895\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-45895\nhttps://lore.kernel.org/linux-cve-announce/2026052718-CVE-2026-45895-959d@gregkh/T"], "threat_severity": "Low"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[576215cffdefc1f0ceebffd87abb390926e6b037,37ccd48cf35f3c8b9f2ea961a7b486b91eb71a82)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[576215cffdefc1f0ceebffd87abb390926e6b037,414259caf81a397563fc9baca9c0ef856c4a97cf)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[576215cffdefc1f0ceebffd87abb390926e6b037,02bb1500f1479750e6557c8044f6a2d7e9d30c12)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[576215cffdefc1f0ceebffd87abb390926e6b037,53b2314b26b6640a3657cc924de63a1a8f26ac4d)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[576215cffdefc1f0ceebffd87abb390926e6b037,77449e453dfc006ad738dec55374c4cbc056fd39)"}}], "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": "generic", "value": "6.5"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[0,6.5)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.6.128,7.0.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.12.75,6.13.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.14,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.19.4,6.20.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,*]"}}], "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": "2026-05-27T16:00:08.702926+00:00", "updated": "2026-08-13T23:15:12.611444+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}