{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2023-53733", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-10-22T13:21:37.350Z", "datePublished": "2025-10-24T11:44:28.115Z", "dateUpdated": "2026-10-15T21:41:35.062Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T09:15:44.713Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: sched: cls_u32: Undo tcf_bind_filter if u32_replace_hw_knode\n\nWhen u32_replace_hw_knode fails, we need to undo the tcf_bind_filter\noperation done at u32_set_parms."}], "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 vulnerable path is reached through the rtnetlink `RTM_NEWTFILTER` interface (tc filter add/change) on the local system; no network peer can drive filter configuration. Packet transmission only serves to consume the corrupted state afterwards.\nAC:L - Failure of `u32_replace_hw_knode()` is fully attacker-controlled \u2014 setting the `skip_sw` flag on a filter attached to a non-offload-capable device (dummy/veth/lo) makes `tc_setup_cb_add()` return `-EOPNOTSUPP` deterministically on every attempt, with no race and no dependence on state outside the attacker's control.\nPR:L - Only `CAP_NET_ADMIN` within a network namespace is needed, which any unprivileged local user obtains with `unshare -Urn` before creating a dummy device, an HTB qdisc with classes, and u32 filters. Per kernel CNA guidance, tc/qdisc paths reachable via user namespaces are PR:L, not PR:H.\nUI:N - The attacker performs the entire sequence (create qdisc/class, repeatedly issue the failing filter add, delete the class, send traffic) unaided. No victim action is required at any point.\nS:U - The corrupted `filter_cnt` accounting and the resulting freed `htb_class` object both live in the kernel of the same machine, so the impact stays within a single security authority. This is standard kernel-local privilege escalation, not a hypervisor or IOMMU boundary crossing.\nC:H - The refcount imbalance permits a still-referenced traffic class to be freed while `res.class` remains a dangling pointer consumed by `htb_classify()`, giving a use-after-free on a slab object the attacker can reallocate and read back. Per guidance, a UAF that grants control over freed-object contents is High confidentiality impact.\nI:H - The same use-after-free lets a sprayed replacement object supply `cl->level`, `cl->leaf.q` and the qdisc function pointers dereferenced in the enqueue path, yielding a write/control-flow-hijack primitive \u2014 the same primitive that produced working local privilege escalation for the sibling cls_u32 tcf_result bugs. Type-confused/UAF corruption of kernel objects is High integrity impact.\nA:H - Even without exploitation, the leaked `filter_cnt` permanently pins the class and its qdisc so `tc class del` always returns `-EBUSY` and the memory is never reclaimed, and the dangling `res.class` dereference in the packet enqueue path oopses the kernel. Any kernel crash or use-after-free is High availability impact."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/sched/cls_u32.c"], "versions": [{"version": "d34e3e181395192d6d1f50dd97bd7854e04e33a4", "lessThan": "a9345793469b65ee5ba7b033239916c2a67d3dd4", "status": "affected", "versionType": "git"}, {"version": "d34e3e181395192d6d1f50dd97bd7854e04e33a4", "lessThan": "025159ed118ba5145b241d574edadb0e00d3c20f", "status": "affected", "versionType": "git"}, {"version": "d34e3e181395192d6d1f50dd97bd7854e04e33a4", "lessThan": "9cb36faedeafb9720ac236aeae2ea57091d90a09", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/sched/cls_u32.c"], "versions": [{"version": "4.7", "status": "affected"}, {"version": "0", "lessThan": "4.7", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.42", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.4.7", "lessThanOrEqual": "6.4.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.5", "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": "4.7", "versionEndExcluding": "6.1.42"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.7", "versionEndExcluding": "6.4.7"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.7", "versionEndExcluding": "6.5"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/a9345793469b65ee5ba7b033239916c2a67d3dd4"}, {"url": "https://git.kernel.org/stable/c/025159ed118ba5145b241d574edadb0e00d3c20f"}, {"url": "https://git.kernel.org/stable/c/9cb36faedeafb9720ac236aeae2ea57091d90a09"}], "title": "net: sched: cls_u32: Undo tcf_bind_filter if u32_replace_hw_knode", "x_generator": {"engine": "bippy-1.2.0"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2023-53733", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2026-10-15T21:36:55.863710Z"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-15T21:41:35.062Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2023-53733", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2026-10-15T21:36:55.863710Z"}}}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-15T21:36:56.348Z"}}], "cna": {"title": "net: sched: cls_u32: Undo tcf_bind_filter if u32_replace_hw_knode", "metrics": [{"cvssV3_1": {"version": "3.1", "baseScore": 7.8, "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}, "scenarios": [{"lang": "en", "value": "AV:L - The vulnerable path is reached through the rtnetlink `RTM_NEWTFILTER` interface (tc filter add/change) on the local system; no network peer can drive filter configuration. Packet transmission only serves to consume the corrupted state afterwards.\nAC:L - Failure of `u32_replace_hw_knode()` is fully attacker-controlled \u2014 setting the `skip_sw` flag on a filter attached to a non-offload-capable device (dummy/veth/lo) makes `tc_setup_cb_add()` return `-EOPNOTSUPP` deterministically on every attempt, with no race and no dependence on state outside the attacker's control.\nPR:L - Only `CAP_NET_ADMIN` within a network namespace is needed, which any unprivileged local user obtains with `unshare -Urn` before creating a dummy device, an HTB qdisc with classes, and u32 filters. Per kernel CNA guidance, tc/qdisc paths reachable via user namespaces are PR:L, not PR:H.\nUI:N - The attacker performs the entire sequence (create qdisc/class, repeatedly issue the failing filter add, delete the class, send traffic) unaided. No victim action is required at any point.\nS:U - The corrupted `filter_cnt` accounting and the resulting freed `htb_class` object both live in the kernel of the same machine, so the impact stays within a single security authority. This is standard kernel-local privilege escalation, not a hypervisor or IOMMU boundary crossing.\nC:H - The refcount imbalance permits a still-referenced traffic class to be freed while `res.class` remains a dangling pointer consumed by `htb_classify()`, giving a use-after-free on a slab object the attacker can reallocate and read back. Per guidance, a UAF that grants control over freed-object contents is High confidentiality impact.\nI:H - The same use-after-free lets a sprayed replacement object supply `cl->level`, `cl->leaf.q` and the qdisc function pointers dereferenced in the enqueue path, yielding a write/control-flow-hijack primitive \u2014 the same primitive that produced working local privilege escalation for the sibling cls_u32 tcf_result bugs. Type-confused/UAF corruption of kernel objects is High integrity impact.\nA:H - Even without exploitation, the leaked `filter_cnt` permanently pins the class and its qdisc so `tc class del` always returns `-EBUSY` and the memory is never reclaimed, and the dangling `res.class` dereference in the packet enqueue path oopses the kernel. Any kernel crash or use-after-free is High availability impact."}]}], "affected": [{"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "d34e3e181395192d6d1f50dd97bd7854e04e33a4", "lessThan": "a9345793469b65ee5ba7b033239916c2a67d3dd4", "versionType": "git"}, {"status": "affected", "version": "d34e3e181395192d6d1f50dd97bd7854e04e33a4", "lessThan": "025159ed118ba5145b241d574edadb0e00d3c20f", "versionType": "git"}, {"status": "affected", "version": "d34e3e181395192d6d1f50dd97bd7854e04e33a4", "lessThan": "9cb36faedeafb9720ac236aeae2ea57091d90a09", "versionType": "git"}], "programFiles": ["net/sched/cls_u32.c"], "defaultStatus": "unaffected"}, {"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "4.7"}, {"status": "unaffected", "version": "0", "lessThan": "4.7", "versionType": "semver"}, {"status": "unaffected", "version": "6.1.42", "versionType": "semver", "lessThanOrEqual": "6.1.*"}, {"status": "unaffected", "version": "6.4.7", "versionType": "semver", "lessThanOrEqual": "6.4.*"}, {"status": "unaffected", "version": "6.5", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*"}], "programFiles": ["net/sched/cls_u32.c"], "defaultStatus": "affected"}], "references": [{"url": "https://git.kernel.org/stable/c/a9345793469b65ee5ba7b033239916c2a67d3dd4"}, {"url": "https://git.kernel.org/stable/c/025159ed118ba5145b241d574edadb0e00d3c20f"}, {"url": "https://git.kernel.org/stable/c/9cb36faedeafb9720ac236aeae2ea57091d90a09"}], "x_generator": {"engine": "bippy-1.2.0"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: sched: cls_u32: Undo tcf_bind_filter if u32_replace_hw_knode\n\nWhen u32_replace_hw_knode fails, we need to undo the tcf_bind_filter\noperation done at u32_set_parms."}], "cpeApplicability": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.1.42", "versionStartIncluding": "4.7"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.4.7", "versionStartIncluding": "4.7"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.5", "versionStartIncluding": "4.7"}], "operator": "OR"}]}], "providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T09:15:44.713Z"}}}, "cveMetadata": {"cveId": "CVE-2023-53733", "state": "PUBLISHED", "dateUpdated": "2026-10-15T21:41:35.062Z", "dateReserved": "2025-10-22T13:21:37.350Z", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "datePublished": "2025-10-24T11:44:28.115Z", "assignerShortName": "Linux"}, "dataVersion": "5.2"}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["net/sched/cls_u32.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "a9345793469b65ee5ba7b033239916c2a67d3dd4", "status": "affected", "version": "d34e3e181395192d6d1f50dd97bd7854e04e33a4", "versionType": "git"}, {"lessThan": "025159ed118ba5145b241d574edadb0e00d3c20f", "status": "affected", "version": "d34e3e181395192d6d1f50dd97bd7854e04e33a4", "versionType": "git"}, {"lessThan": "9cb36faedeafb9720ac236aeae2ea57091d90a09", "status": "affected", "version": "d34e3e181395192d6d1f50dd97bd7854e04e33a4", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["net/sched/cls_u32.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "4.7"}, {"lessThan": "4.7", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.1.*", "status": "unaffected", "version": "6.1.42", "versionType": "semver"}, {"lessThanOrEqual": "6.4.*", "status": "unaffected", "version": "6.4.7", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "6.5", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: sched: cls_u32: Undo tcf_bind_filter if u32_replace_hw_knode\n\nWhen u32_replace_hw_knode fails, we need to undo the tcf_bind_filter\noperation done at u32_set_parms."}], "id": "CVE-2023-53733", "lastModified": "2026-10-15T22:17:47.800", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2023-53733", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "total"}], "role": "CISA Coordinator", "timestamp": "2026-10-15T21:36:55.863710Z", "version": "2.0.3"}}]}, "published": "2025-10-24T12:15:35.617", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/025159ed118ba5145b241d574edadb0e00d3c20f"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/9cb36faedeafb9720ac236aeae2ea57091d90a09"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/a9345793469b65ee5ba7b033239916c2a67d3dd4"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Deferred"}

{"bugzilla": {"description": "kernel: net: sched: cls_u32: Undo tcf_bind_filter if u32_replace_hw_knode", "id": "2406197", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2406197"}, "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"}, "details": ["No description is available for this CVE."], "name": "CVE-2023-53733", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Not affected", "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": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "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": "2025-10-24T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2023-53733\nhttps://nvd.nist.gov/vuln/detail/CVE-2023-53733\nhttps://lore.kernel.org/linux-cve-announce/2025102432-CVE-2023-53733-8b6c@gregkh/T"], "threat_severity": "Moderate"}

{"created": "2025-10-27T22:13:06.728691+00:00", "updated": "2025-10-27T22:13:06.728718+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}