{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2023-52523","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2024-02-20T12:30:33.317Z","datePublished":"2024-03-02T21:52:30.351Z","dateUpdated":"2026-08-05T09:10:23.650Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T09:10:23.650Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf, sockmap: Reject sk_msg egress redirects to non-TCP sockets\n\nWith a SOCKMAP/SOCKHASH map and an sk_msg program user can steer messages\nsent from one TCP socket (s1) to actually egress from another TCP\nsocket (s2):\n\ntcp_bpf_sendmsg(s1)\t\t// = sk_prot->sendmsg\n  tcp_bpf_send_verdict(s1)\t// __SK_REDIRECT case\n    tcp_bpf_sendmsg_redir(s2)\n      tcp_bpf_push_locked(s2)\n\ttcp_bpf_push(s2)\n\t  tcp_rate_check_app_limited(s2) // expects tcp_sock\n\t  tcp_sendmsg_locked(s2)\t // ditto\n\nThere is a hard-coded assumption in the call-chain, that the egress\nsocket (s2) is a TCP socket.\n\nHowever in commit 122e6c79efe1 (\"sock_map: Update sock type checks for\nUDP\") we have enabled redirects to non-TCP sockets. This was done for the\nsake of BPF sk_skb programs. There was no indention to support sk_msg\nsend-to-egress use case.\n\nAs a result, attempts to send-to-egress through a non-TCP socket lead to a\ncrash due to invalid downcast from sock to tcp_sock:\n\n BUG: kernel NULL pointer dereference, address: 000000000000002f\n ...\n Call Trace:\n  <TASK>\n  ? show_regs+0x60/0x70\n  ? __die+0x1f/0x70\n  ? page_fault_oops+0x80/0x160\n  ? do_user_addr_fault+0x2d7/0x800\n  ? rcu_is_watching+0x11/0x50\n  ? exc_page_fault+0x70/0x1c0\n  ? asm_exc_page_fault+0x27/0x30\n  ? tcp_tso_segs+0x14/0xa0\n  tcp_write_xmit+0x67/0xce0\n  __tcp_push_pending_frames+0x32/0xf0\n  tcp_push+0x107/0x140\n  tcp_sendmsg_locked+0x99f/0xbb0\n  tcp_bpf_push+0x19d/0x3a0\n  tcp_bpf_sendmsg_redir+0x55/0xd0\n  tcp_bpf_send_verdict+0x407/0x550\n  tcp_bpf_sendmsg+0x1a1/0x390\n  inet_sendmsg+0x6a/0x70\n  sock_sendmsg+0x9d/0xc0\n  ? sockfd_lookup_light+0x12/0x80\n  __sys_sendto+0x10e/0x160\n  ? syscall_enter_from_user_mode+0x20/0x60\n  ? __this_cpu_preempt_check+0x13/0x20\n  ? lockdep_hardirqs_on+0x82/0x110\n  __x64_sys_sendto+0x1f/0x30\n  do_syscall_64+0x38/0x90\n  entry_SYSCALL_64_after_hwframe+0x63/0xcd\n\nReject selecting a non-TCP sockets as redirect target from a BPF sk_msg\nprogram to prevent the crash. When attempted, user will receive an EACCES\nerror from send/sendto/sendmsg() syscall."}],"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 - Exploitation requires local bpf() setup of a SOCKMAP/SOCKHASH with an sk_msg verdict program plus send/sendto/sendmsg on a sockmap-enrolled TCP socket; the crash path is the local tcp_bpf_sendmsg → tcp_bpf_sendmsg_redir chain, not remote packet processing.\nAC:L - The attacker fully controls map population (TCP source and non-TCP redirect target), the sk_msg redirect verdict, and the triggering sendmsg; the type confusion is deterministic and needs no race or uncontrolled layout.\nPR:L - SOCKMAP/sk_msg creation needs CAP_NET_ADMIN/CAP_BPF, but those are commonly held by networking containers and can be delegated via BPF tokens; once a sockmap sk_msg redirect path exists, the send trigger is an ordinary local operation, matching other sockmap scores.\nUI:N - The attacker performs map setup, program attach, and the triggering sendmsg themselves; no victim action is required.\nS:U - The type confusion and resulting heap OOB/crash remain inside the host kernel’s security authority; this is standard local kernel impact, not a VM/IOMMU/sandbox boundary crossing.\nC:H - tcp_bpf_push runs tcp_rate_check_app_limited() on the non-TCP target, reading tcp_sock fields (e.g. write_seq/mss_cache/delivered at offsets ≥1480) past udp_sock (1344) or unix_sock (1152), i.e. heap OOB reads of adjacent groomable objects.\nI:H - The same path writes tp->app_limited at offset 1780 past the smaller socket object (heap OOB write), and treating a non-TCP sock as tcp_sock is type confusion, which is High integrity impact under scoring guidance.\nA:H - The demonstrated result is a kernel NULL pointer dereference in tcp_tso_segs (icsk_ca_ops) reached via tcp_sendmsg_locked, causing an oops/panic that the attacker can repeat at will."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/core/sock_map.c"],"versions":[{"version":"122e6c79efe1c25816118aca9cfabe54e99c2432","lessThan":"bc8b89b6963803a123f64aa9494155a037b3d728","status":"affected","versionType":"git"},{"version":"122e6c79efe1c25816118aca9cfabe54e99c2432","lessThan":"b8f97e47b6fb84fcf2f5a22e725eefb6cf5070c2","status":"affected","versionType":"git"},{"version":"122e6c79efe1c25816118aca9cfabe54e99c2432","lessThan":"ded6e448028f0f91b6af35985afca01fa02a9089","status":"affected","versionType":"git"},{"version":"122e6c79efe1c25816118aca9cfabe54e99c2432","lessThan":"b80e31baa43614e086a9d29dc1151932b1bd7fc5","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/core/sock_map.c"],"versions":[{"version":"5.13","status":"affected"},{"version":"0","lessThan":"5.13","status":"unaffected","versionType":"semver"},{"version":"5.15.135","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.57","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.5.7","lessThanOrEqual":"6.5.*","status":"unaffected","versionType":"semver"},{"version":"6.6","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":"5.13","versionEndExcluding":"5.15.135"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"6.1.57"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"6.5.7"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"6.6"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/bc8b89b6963803a123f64aa9494155a037b3d728"},{"url":"https://git.kernel.org/stable/c/b8f97e47b6fb84fcf2f5a22e725eefb6cf5070c2"},{"url":"https://git.kernel.org/stable/c/ded6e448028f0f91b6af35985afca01fa02a9089"},{"url":"https://git.kernel.org/stable/c/b80e31baa43614e086a9d29dc1151932b1bd7fc5"}],"title":"bpf, sockmap: Reject sk_msg egress redirects to non-TCP sockets","x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2023-52523","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2024-03-04T15:32:59.403562Z"}}}],"providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2024-06-04T17:22:46.142Z"}},{"providerMetadata":{"orgId":"af854a3a-2127-422b-91ae-364da2661108","shortName":"CVE","dateUpdated":"2024-08-02T23:03:20.665Z"},"title":"CVE Program Container","references":[{"url":"https://git.kernel.org/stable/c/bc8b89b6963803a123f64aa9494155a037b3d728","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/b8f97e47b6fb84fcf2f5a22e725eefb6cf5070c2","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/ded6e448028f0f91b6af35985afca01fa02a9089","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/b80e31baa43614e086a9d29dc1151932b1bd7fc5","tags":["x_transferred"]}]}]}}