{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2023-52843 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2023-52843 is a medium-severity vulnerability in Linux kernel, published on 21 May 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-2023-52843 and fix it if it is affected.\n\nWhat it is: CVE-2023-52843 is a medium-severity vulnerability in Linux kernel, published on 21 May 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-2023-52843 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-2023-52843/ (Markdown: https://insights.sbomify.com/CVE-2023-52843/index.md)","id":"CVE-2023-52843","markdown":"https://insights.sbomify.com/CVE-2023-52843/index.md","name":"CVE-2023-52843","record":{"aliases":["BELL-CVE-2023-52843","DEBIAN-CVE-2023-52843","GHSA-jm7v-c85h-4vvr","UBUNTU-CVE-2023-52843"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Linux kernel","requires_auth":"low_privilege","summary":"A missing length check in the Linux kernel LLC module allows local attackers to trigger a kernel crash via crafted network packets.","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":"nvd","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-908","name":"Use of Uninitialized Resource"}],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nllc: verify mac len before reading mac header\n\nLLC reads the mac header with eth_hdr without verifying that the skb\nhas an Ethernet header.\n\nSyzbot was able to enter llc_rcv on a tun device. Tun can insert\npackets without mac len and with user configurable skb-\u003eprotocol\n(passing a tun_pi header when not configuring IFF_NO_PI).\n\n    BUG: KMSAN: uninit-value in llc_station_ac_send_test_r net/llc/llc_station.c:81 [inline]\n    BUG: KMSAN: uninit-value in llc_station_rcv+0x6fb/0x1290 net/llc/llc_station.c:111\n    llc_station_ac_send_test_r net/llc/llc_station.c:81 [inline]\n    llc_station_rcv+0x6fb/0x1290 net/llc/llc_station.c:111\n    llc_rcv+0xc5d/0x14a0 net/llc/llc_input.c:218\n    __netif_receive_skb_one_core net/core/dev.c:5523 [inline]\n    __netif_receive_skb+0x1a6/0x5a0 net/core/dev.c:5637\n    netif_receive_skb_internal net/core/dev.c:5723 [inline]\n    netif_receive_skb+0x58/0x660 net/core/dev.c:5782\n    tun_rx_batched+0x3ee/0x980 drivers/net/tun.c:1555\n    tun_get_user+0x54c5/0x69c0 drivers/net/tun.c:2002\n\nAdd a mac_len test before all three eth_hdr(skb) calls under net/llc.\n\nThere are further uses in include/net/llc_pdu.h. All these are\nprotected by a test skb-\u003eprotocol == ETH_P_802_2. Which does not\nprotect against this tun scenario.\n\nBut the mac_len test added in this patch in llc_fixup_skb will\nindirectly protect those too. That is called from llc_rcv before any\nother LLC code.\n\nIt is tempting to just add a blanket mac_len check in llc_rcv, but\nnot sure whether that could break valid LLC paths that do not assume\nan Ethernet header. 802.2 LLC may be used on top of non-802.3\nprotocols in principle. The below referenced commit shows that used\nto, on top of Token Ring.\n\nAt least one of the three eth_hdr uses goes back to before the start\nof git history. But the one that syzbot exercises is introduced in\nthis commit. That commit is old enough (2008), that effectively all\nstable kernels should receive this.","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":"llc: verify mac len before reading mac header","id":"CVE-2023-52843","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"null_dereference","year":"2023"},"n_packages":0,"n_references":9,"next":{"headline":"media: vidtv: psi: Add check for kstrdup","id":"CVE-2023-52844"},"packages":[],"prev":{"headline":"virtio/vsock: Fix uninit-value in virtio_transport_recv_pkt()","id":"CVE-2023-52842"},"products":["Linux"],"published":"2024-05-21","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 missing length check in the Linux kernel LLC module allows local attackers to trigger a kernel crash via crafted network packets.","url":"https://insights.sbomify.com/CVE-2023-52843/"}