Answer in brief
CVE-2023-52523 records a High severity (CVSS 7.8) vulnerability in bpf, sockmap: Reject sk_msg egress redirects to non-TCP sockets. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:6.6:rc1:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:6.6:rc2:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:6.6:rc3:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:6.6:rc4:*:*:*:*:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=122e6c79efe1c25816118aca9cfabe54e99c2432 <bc8b89b6963803a123f64aa9494155a037b3d728 || >=122e6c79efe1c25816118aca9cfabe54e99c2432 <b8f97e47b6fb84fcf2f5a22e725eefb6cf5070c2 || >=122e6c79efe1c25816118aca9cfabe54e99c2432 <ded6e448028f0f91b6af35985afca01fa02a9089 || >=122e6c79efe1c25816118aca9cfabe54e99c2432 <b80e31baa43614e086a9d29dc1151932b1bd7fc5 | bc8b89b6963803a123f64aa9494155a037b3d728, b8f97e47b6fb84fcf2f5a22e725eefb6cf5070c2, ded6e448028f0f91b6af35985afca01fa02a9089, b80e31baa43614e086a9d29dc1151932b1bd7fc5 |
| Linux/Linuxgeneric | 5.13 | Not reported |
Published upstream
Mar 2, 2024
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 5, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 4, 2026
In the Linux kernel, the following vulnerability has been resolved: bpf, sockmap: Reject sk_msg egress redirects to non-TCP sockets With a SOCKMAP/SOCKHASH map and an sk_msg program user can steer messages sent from one TCP socket (s1) to actually egress from another TCP socket (s2): tcp_bpf_sendmsg(s1) // = sk_prot->sendmsg tcp_bpf_send_verdict(s1) // __SK_REDIRECT case tcp_bpf_sendmsg_redir(s2) tcp_bpf_push_locked(s2) tcp_bpf_push(s2) tcp_rate_check_app_limited(s2) // expects tcp_sock tcp_sendmsg_locked(s2) // ditto There is a hard-coded assumption in the call-chain, that the egress socket (s2) is a TCP socket. However in commit 122e6c79efe1 ("sock_map: Update sock type checks for UDP") we have enabled redirects to non-TCP sockets. This was done for the sake of BPF sk_skb programs. There was no indention to support sk_msg send-to-egress use case. As a result, attempts to send-to-egress through a non-TCP socket lead to a crash due to invalid downcast from sock to tcp_sock: BUG: kernel NULL pointer dereference, address: 000000000000002f ... Call Trace: <TASK> ? show_regs+0x60/0x70 ? __die+0x1f/0x70 ? page_fault_oops+0x80/0x160 ? do_user_addr_fault+0x2d7/0x800 ? rcu_is_watching+0x11/0x50 ? exc_page_fault+0x70/0x1c0 ? asm_exc_page_fault+0x27/0x30 ? tcp_tso_segs+0x14/0xa0 tcp_write_xmit+0x67/0xce0 __tcp_push_pending_frames+0x32/0xf0 tcp_push+0x107/0x140 tcp_sendmsg_locked+0x99f/0xbb0 tcp_bpf_push+0x19d/0x3a0 tcp_bpf_sendmsg_redir+0x55/0xd0 tcp_bpf_send_verdict+0x407/0x550 tcp_bpf_sendmsg+0x1a1/0x390 inet_sendmsg+0x6a/0x70 sock_sendmsg+0x9d/0xc0 ? sockfd_lookup_light+0x12/0x80 __sys_sendto+0x10e/0x160 ? syscall_enter_from_user_mode+0x20/0x60 ? __this_cpu_preempt_check+0x13/0x20 ? lockdep_hardirqs_on+0x82/0x110 __x64_sys_sendto+0x1f/0x30 do_syscall_64+0x38/0x90 entry_SYSCALL_64_after_hwframe+0x63/0xcd Reject selecting a non-TCP sockets as redirect target from a BPF sk_msg program to prevent the crash. When attempted, user will receive an EACCES error from send/sendto/sendmsg() syscall.
Quoted source text, attributed separately from HOL analysis.