{"id":"DEBIAN-CVE-2023-53517","details":"In the Linux kernel, the following vulnerability has been resolved:  tipc: do not update mtu if msg_max is too small in mtu negotiation  When doing link mtu negotiation, a malicious peer may send Activate msg with a very small mtu, e.g. 4 in Shuang's testing, without checking for the minimum mtu, l-\u003emtu will be set to 4 in tipc_link_proto_rcv(), then n-\u003elinks[bearer_id].mtu is set to 4294967228, which is a overflow of '4 - INT_H_SIZE - EMSG_OVERHEAD' in tipc_link_mss().  With tipc_link.mtu = 4, tipc_link_xmit() kept printing the warning:   tipc: Too large msg, purging xmit list 1 5 0 40 4!  tipc: Too large msg, purging xmit list 1 15 0 60 4!  And with tipc_link_entry.mtu 4294967228, a huge skb was allocated in named_distribute(), and when purging it in tipc_link_xmit(), a crash was even caused:    general protection fault, probably for non-canonical address 0x2100001011000dd: 0000 [#1] PREEMPT SMP PTI   CPU: 0 PID: 0 Comm: swapper/0 Kdump: loaded Not tainted 6.3.0.neta #19   RIP: 0010:kfree_skb_list_reason+0x7e/0x1f0   Call Trace:    \u003cIRQ\u003e    skb_release_data+0xf9/0x1d0    kfree_skb_reason+0x40/0x100    tipc_link_xmit+0x57a/0x740 [tipc]    tipc_node_xmit+0x16c/0x5c0 [tipc]    tipc_named_node_up+0x27f/0x2c0 [tipc]    tipc_node_write_unlock+0x149/0x170 [tipc]    tipc_rcv+0x608/0x740 [tipc]    tipc_udp_recv+0xdc/0x1f0 [tipc]    udp_queue_rcv_one_skb+0x33e/0x620    udp_unicast_rcv_skb.isra.72+0x75/0x90    __udp4_lib_rcv+0x56d/0xc20    ip_protocol_deliver_rcu+0x100/0x2d0  This patch fixes it by checking the new mtu against tipc_bearer_min_mtu(), and not updating mtu if it is too small.","modified":"2026-09-15T09:03:02.699452930Z","published":"2025-10-01T12:15:55.873Z","upstream":["CVE-2023-53517"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2023-53517"}],"affected":[{"package":{"name":"linux","ecosystem":"Debian:12","purl":"pkg:deb/debian/linux?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.1.37-1"}]}],"versions":["6.1.27-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2023-53517.json"}},{"package":{"name":"linux","ecosystem":"Debian:13","purl":"pkg:deb/debian/linux?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.3.7-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2023-53517.json"}},{"package":{"name":"linux","ecosystem":"Debian:14","purl":"pkg:deb/debian/linux?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.3.7-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2023-53517.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}