{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2021-47592 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2021-47592 is a medium-severity vulnerability in Linux kernel, published on 19 Jun 2024. It can only be exploited from the same machine or local network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2021-47592 and fix it if it is affected.\n\nWhat it is: CVE-2021-47592 is a medium-severity vulnerability in Linux kernel, published on 19 Jun 2024. It can only be exploited from the same machine or local network, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2021-47592 in the wild and no public exploit code.\n\nAffected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2021-47592/ (Markdown: https://insights.sbomify.com/CVE-2021-47592/index.md)","id":"CVE-2021-47592","markdown":"https://insights.sbomify.com/CVE-2021-47592/index.md","name":"CVE-2021-47592","record":{"aliases":["DEBIAN-CVE-2021-47592","GHSA-8c7q-xg4v-xr24","UBUNTU-CVE-2021-47592"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":true,"product_category":"Linux kernel network driver","requires_auth":"low_privilege","summary":"A local attacker can cause a kernel crash by deleting a specific traffic control filter, leading to denial of service.","user_interaction":"not_required","vuln_class":"null_dereference"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[{"product":"linux_kernel","vendor":"linux"}],"cvss":{"score":5.5,"severity":"medium","source":"cisa-adp","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"cwes":[{"id":"CWE-476","name":"NULL Pointer Dereference"}],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: stmmac: fix tc flower deletion for VLAN priority Rx steering\n\nTo replicate the issue:-\n\n1) Add 1 flower filter for VLAN Priority based frame steering:-\n$ IFDEVNAME=eth0\n$ tc qdisc add dev $IFDEVNAME ingress\n$ tc qdisc add dev $IFDEVNAME root mqprio num_tc 8 \\\n   map 0 1 2 3 4 5 6 7 0 0 0 0 0 0 0 0 \\\n   queues 1@0 1@1 1@2 1@3 1@4 1@5 1@6 1@7 hw 0\n$ tc filter add dev $IFDEVNAME parent ffff: protocol 802.1Q \\\n   flower vlan_prio 0 hw_tc 0\n\n2) Get the 'pref' id\n$ tc filter show dev $IFDEVNAME ingress\n\n3) Delete a specific tc flower record (say pref 49151)\n$ tc filter del dev $IFDEVNAME parent ffff: pref 49151\n\nFrom dmesg, we will observe kernel NULL pointer ooops\n\n[  197.170464] BUG: kernel NULL pointer dereference, address: 0000000000000000\n[  197.171367] #PF: supervisor read access in kernel mode\n[  197.171367] #PF: error_code(0x0000) - not-present page\n[  197.171367] PGD 0 P4D 0\n[  197.171367] Oops: 0000 [#1] PREEMPT SMP NOPTI\n\n\u003csnip\u003e\n\n[  197.171367] RIP: 0010:tc_setup_cls+0x20b/0x4a0 [stmmac]\n\n\u003csnip\u003e\n\n[  197.171367] Call Trace:\n[  197.171367]  \u003cTASK\u003e\n[  197.171367]  ? __stmmac_disable_all_queues+0xa8/0xe0 [stmmac]\n[  197.171367]  stmmac_setup_tc_block_cb+0x70/0x110 [stmmac]\n[  197.171367]  tc_setup_cb_destroy+0xb3/0x180\n[  197.171367]  fl_hw_destroy_filter+0x94/0xc0 [cls_flower]\n\nThe above issue is due to previous incorrect implementation of\ntc_del_vlan_flow(), shown below, that uses flow_cls_offload_flow_rule()\nto get struct flow_rule *rule which is no longer valid for tc filter\ndelete operation.\n\n  struct flow_rule *rule = flow_cls_offload_flow_rule(cls);\n  struct flow_dissector *dissector = rule-\u003ematch.dissector;\n\nSo, to ensure tc_del_vlan_flow() deletes the right VLAN cls record for\nearlier configured RX queue (configured by hw_tc) in tc_add_vlan_flow(),\nthis patch introduces stmmac_rfs_entry as driver-side flow_cls_offload\nrecord for 'RX frame steering' tc flower, currently used for VLAN\npriority. The implementation has taken consideration for future extension\nto include other type RX frame steering such as EtherType based.\n\nv2:\n - Clean up overly extensive backtrace and rewrite git message to better\n   explain the kernel NULL pointer issue.","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"net: stmmac: fix tc flower deletion for VLAN priority Rx steering","id":"CVE-2021-47592","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"null_dereference","year":"2021"},"n_packages":0,"n_references":2,"next":{"headline":"mptcp: clear 'kern' flag from fallback sockets","id":"CVE-2021-47593"},"packages":[],"prev":{"headline":"mptcp: remove tcp ulp setsockopt support","id":"CVE-2021-47591"},"products":["Linux"],"published":"2024-06-19","related":[{"cvss_score":8.8,"headline":"Linux Kernel Out-of-Bounds Write","id":"CVE-2026-53266","kev_date_added":"2026-09-18","published":"2026-06-25"},{"cvss_score":8.8,"headline":"Linux Kernel Improper Input Validation","id":"CVE-2013-6282","kev_date_added":"2022-09-15","published":"2013-11-19"},{"cvss_score":8.4,"headline":"Linux Kernel Heap-Based Buffer Overflow","id":"CVE-2022-0185","kev_date_added":"2024-08-21","published":"2022-02-11"},{"cvss_score":8.4,"headline":"Linux Kernel Privilege Escalation","id":"CVE-2013-2094","kev_date_added":"2022-09-15","published":"2013-05-14"},{"cvss_score":7.8,"headline":"Linux Kernel Unspecified","id":"CVE-2026-53362","kev_date_added":"2026-08-27","published":"2026-07-04"},{"cvss_score":7.8,"headline":"Linux Kernel Missing Initialization of a Variable","id":"CVE-2026-46300","kev_date_added":"2026-10-28","published":"2026-05-23"},{"cvss_score":7.8,"headline":"Linux Kernel Race Condition","id":"CVE-2025-39964","kev_date_added":"2026-09-18","published":"2025-10-13"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-05-11","vendors":["Linux"]},"summary":"A local attacker can cause a kernel crash by deleting a specific traffic control filter, leading to denial of service.","url":"https://insights.sbomify.com/CVE-2021-47592/"}