{"cve":"CVE-2025-39913","nvd":{"published":"2025-10-01T08:15:34.390","modified":"2026-10-19T21:10:00.160","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ntcp_bpf: Call sk_msg_free() when tcp_bpf_send_verdict() fails to allocate psock->cork.\n\nsyzbot reported the splat below. [0]\n\nThe repro does the following:\n\n  1. Load a sk_msg prog that calls bpf_msg_cork_bytes(msg, cork_bytes)\n  2. Attach the prog to a SOCKMAP\n  3. Add a socket to the SOCKMAP\n  4. Activate fault injection\n  5. Send data less than cork_bytes\n\nAt 5., the data is carried over to the next sendmsg() as it is\nsmaller than the cork_bytes specified by bpf_msg_cork_bytes().\n\nThen, tcp_bpf_send_verdict() tries to allocate psock->cork to hold\nthe data, but this fails silently due to fault injection + __GFP_NOWARN.\n\nIf the allocation fails, we need to revert the sk->sk_forward_alloc\nchange done by sk_msg_alloc().\n\nLet's call sk_msg_free() when tcp_bpf_send_verdict fails to allocate\npsock->cork.\n\nThe \"*copied\" also needs to be updated such that a proper error can\nbe returned to the caller, sendmsg. It fails to allocate psock->cork.\nNothing has been corked so far, so this patch simply sets \"*copied\"\nto 0.\n\n[0]:\nWARNING: net/ipv4/af_inet.c:156 at inet_sock_destruct+0x623/0x730 net/ipv4/af_inet.c:156, CPU#1: syz-executor/5983\nModules linked in:\nCPU: 1 UID: 0 PID: 5983 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full)\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025\nRIP: 0010:inet_sock_destruct+0x623/0x730 net/ipv4/af_inet.c:156\nCode: 0f 0b 90 e9 62 fe ff ff e8 7a db b5 f7 90 0f 0b 90 e9 95 fe ff ff e8 6c db b5 f7 90 0f 0b 90 e9 bb fe ff ff e8 5e db b5 f7 90 <0f> 0b 90 e9 e1 fe ff ff 89 f9 80 e1 07 80 c1 03 38 c1 0f 8c 9f fc\nRSP: 0018:ffffc90000a08b48 EFLAGS: 00010246\nRAX: ffffffff8a09d0b2 RBX: dffffc0000000000 RCX: ffff888024a23c80\nRDX: 0000000000000100 RSI: 0000000000000fff RDI: 0000000000000000\nRBP: 0000000000000fff R08: ffff88807e07c627 R09: 1ffff1100fc0f8c4\nR10: dffffc0000000000 R11: ffffed100fc0f8c5 R12: ffff88807e07c380\nR13: dffffc0000000000 R14: ffff88807e07c60c R15: 1ffff1100fc0f872\nFS:  00005555604c4500(0000) GS:ffff888125af1000(0000) knlGS:0000000000000000\nCS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 00005555604df5c8 CR3: 0000000032b06000 CR4: 00000000003526f0\nCall Trace:\n <IRQ>\n __sk_destruct+0x86/0x660 net/core/sock.c:2339\n rcu_do_batch kernel/rcu/tree.c:2605 [inline]\n rcu_core+0xca8/0x1770 kernel/rcu/tree.c:2861\n handle_softirqs+0x286/0x870 kernel/softirq.c:579\n __do_softirq kernel/softirq.c:613 [inline]\n invoke_softirq kernel/softirq.c:453 [inline]\n __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680\n irq_exit_rcu+0x9/0x30 kernel/softirq.c:696\n instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]\n sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1052\n </IRQ>","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8},"cwes":[],"references":["https://git.kernel.org/stable/c/05366527f44cf4b884f3d9462ae8009be9665856","https://git.kernel.org/stable/c/08f58d10f5abf11d297cc910754922498c921f91","https://git.kernel.org/stable/c/539920180c55f5e13a2488a2339f94e6b8cb69e0","https://git.kernel.org/stable/c/66bcb04a441fbf15d66834b7e3eefb313dd750c8","https://git.kernel.org/stable/c/7429b8b9bfbc276fd304fbaebc405f46b421fedf"],"products":["debian:debian_linux","linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-21T03:43:09.190223697+00:00"},"epss":{"cve":"CVE-2025-39913","score":0.00187,"percentile":0.08253,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}