{"cve":"CVE-2023-53517","nvd":{"published":"2025-10-01T12:15:55.873","modified":"2026-10-15T22:17:41.720","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ntipc: do not update mtu if msg_max is too small in mtu negotiation\n\nWhen doing link mtu negotiation, a malicious peer may send Activate msg\nwith a very small mtu, e.g. 4 in Shuang's testing, without checking for\nthe minimum mtu, l->mtu will be set to 4 in tipc_link_proto_rcv(), then\nn->links[bearer_id].mtu is set to 4294967228, which is a overflow of\n'4 - INT_H_SIZE - EMSG_OVERHEAD' in tipc_link_mss().\n\nWith tipc_link.mtu = 4, tipc_link_xmit() kept printing the warning:\n\n tipc: Too large msg, purging xmit list 1 5 0 40 4!\n tipc: Too large msg, purging xmit list 1 15 0 60 4!\n\nAnd with tipc_link_entry.mtu 4294967228, a huge skb was allocated in\nnamed_distribute(), and when purging it in tipc_link_xmit(), a crash\nwas even caused:\n\n  general protection fault, probably for non-canonical address 0x2100001011000dd: 0000 [#1] PREEMPT SMP PTI\n  CPU: 0 PID: 0 Comm: swapper/0 Kdump: loaded Not tainted 6.3.0.neta #19\n  RIP: 0010:kfree_skb_list_reason+0x7e/0x1f0\n  Call Trace:\n   <IRQ>\n   skb_release_data+0xf9/0x1d0\n   kfree_skb_reason+0x40/0x100\n   tipc_link_xmit+0x57a/0x740 [tipc]\n   tipc_node_xmit+0x16c/0x5c0 [tipc]\n   tipc_named_node_up+0x27f/0x2c0 [tipc]\n   tipc_node_write_unlock+0x149/0x170 [tipc]\n   tipc_rcv+0x608/0x740 [tipc]\n   tipc_udp_recv+0xdc/0x1f0 [tipc]\n   udp_queue_rcv_one_skb+0x33e/0x620\n   udp_unicast_rcv_skb.isra.72+0x75/0x90\n   __udp4_lib_rcv+0x56d/0xc20\n   ip_protocol_deliver_rcu+0x100/0x2d0\n\nThis patch fixes it by checking the new mtu against tipc_bearer_min_mtu(),\nand not updating mtu if it is too small.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":5.5},"cwes":[],"references":["https://git.kernel.org/stable/c/1dd7ae5e0cf5a56e513f7ab7ab9570b7496281d2","https://git.kernel.org/stable/c/259683001d7e879fea4b42084fb6560dd9408a7e","https://git.kernel.org/stable/c/2bd4ff4ffb92113f8acd04dbaed83269172c24b4","https://git.kernel.org/stable/c/56077b56cd3fb78e1c8619e29581ba25a5c55e86","https://git.kernel.org/stable/c/575e84d90a74c0b091b3417ba763ebb237aa0a8c"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T22:11:26.888974865+00:00"},"epss":{"cve":"CVE-2023-53517","score":0.00305,"percentile":0.23073,"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."]}