CVE-2025-68227: linux
Vulnerability summary
CVE-2025-68227 is a vulnerability in linux with no CVSS score yet. EPSS estimates a 0.22% chance of exploitation in the next 30 days, higher than 11.3% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 41 · Related 38Timeline
- 16-12-2025PublishedVulnerability first disclosed.
- 11-05-2026Last modifiedVulnerability information updated.
Description
In the Linux kernel, the following vulnerability has been resolved: mptcp: Fix proto fallback detection with BPF The sockmap feature allows bpf syscall from userspace, or based on bpf sockops, replacing the sk_prot of sockets during protocol stack processing with sockmap's custom read/write interfaces. ''' tcp_rcv_state_process() syn_recv_sock()/subflow_syn_recv_sock() tcp_init_transfer(BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB) bpf_skops_established <== sockops bpf_sock_map_update(sk) <== call bpf helper tcp_bpf_update_proto() <== update sk_prot ''' When the server has MPTCP enabled but the client sends a TCP SYN without MPTCP, subflow_syn_recv_sock() performs a fallback on the subflow, replacing the subflow sk's sk_prot with the native sk_prot. ''' subflow_syn_recv_sock() subflow_ulp_fallback() subflow_drop_ctx() mptcp_subflow_ops_undo_override() ''' Then, this subflow can be normally used by sockmap, which replaces the native sk_prot with sockmap's custom sk_prot. The issue occurs when the user executes accept::mptcp_stream_accept::mptcp_fallback_tcp_ops(). Here, it uses sk->sk_prot to compare with the native sk_prot, but this is incorrect when sockmap is used, as we may incorrectly set sk->sk_socket->ops. This fix uses the more generic sk_family for the comparison instead. Additionally, this also prevents a WARNING from occurring: result from ./scripts/decode_stacktrace.sh: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 337 at net/mptcp/protocol.c:68 mptcp_stream_accept \ (net/mptcp/protocol.c:4005) Modules linked in: ... PKRU: 55555554 Call Trace: <TASK> do_accept (net/socket.c:1989) __sys_accept4 (net/socket.c:2028 net/socket.c:2057) __x64_sys_accept (net/socket.c:2067) x64_sys_call (arch/x86/entry/syscall_64.c:41) do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) RIP: 0033:0x7f87ac92b83d ---[ end trace 0000000000000000 ]---
CVSS metrics
Risk metrics not yet published.
EPSS trend
Probability
0.22%
Chance of exploitation in the next 30 days
Percentile
11%
Versus all other CVEs
30-day change
0.00 pp
From 0.22% on 19-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeNo weakness data has been published for this record.
Affected systems
Ubuntu157 products
- linuxAll versions (No fix recorded) | < 5.15.0-173.183 | < 6.8.0-106.106 | < 6.17.0-19.19
- linux-allwinner-5.19All versions (No fix recorded)
- linux-awsAll versions (No fix recorded) | < 5.15.0-1103.110 | < 6.8.0-1050.53 | < 6.17.0-1009.9
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11All versions (No fix recorded)
Debian1 product
- linux< 6.1.159-1 | < 6.12.63-1 | < 6.17.10-1
Linux1 product
- linux≥ 0b4f33def7bbde1ce2fea05f116639270e7acdc7, < 92c4092fe012ecdfa5fb05d394f1c1d8f91ad81c | ≥ 0b4f33def7bbde1ce2fea05f116639270e7acdc7, < 7ee8f015eb47907745e2070184a8ab1e442ac3c4 | ≥ 0b4f33def7bbde1ce2fea05f116639270e7acdc7, < 344974ea1a3ca30e4920687b0091bda4438cebdb | ≥ 0b4f33def7bbde1ce2fea05f116639270e7acdc7, < 037cc50589643342d69185b663ecf9d26cce91e8 | ≥ 0b4f33def7bbde1ce2fea05f116639270e7acdc7, < 9b1980b6f23fa30bf12add19f37c7458625099eb | ≥ 0b4f33def7bbde1ce2fea05f116639270e7acdc7, < 1a0d5c74af9b6ba9ffdf1172de5a1a6df5922a00 | ≥ 0b4f33def7bbde1ce2fea05f116639270e7acdc7, < c77b3b79a92e3345aa1ee296180d1af4e7031f8f | 5.7
3 vendors · 159 products
