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->mtu will be set to 4 in tipc_link_proto_rcv(), then n->links[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: <IRQ> 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.
CVSS Details
- CVSS 3.1 Base Score: 9.8
- CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Amazon Linux Ami 2 | — | Upgrade kernel-debuginfo-common-aarch64Upgrade perfUpgrade kernel-develUpgrade python-perf-debuginfoUpgrade kernelUpgrade kernel-headersUpgrade kernel-debuginfoUpgrade kernel-tools-develUpgrade kernel-tools-debuginfoUpgrade bpftool-debuginfoUpgrade kernel-debuginfo-common-x86_64Upgrade kernel-livepatch-5.10.184-174.730Upgrade bpftoolUpgrade perf-debuginfoUpgrade python-perfUpgrade kernel-tools | May 20, 2026 | May 20, 2026 |
| Debian | — | Upgrade linux | Oct 3, 2025 | Oct 3, 2025 |
| Huawei Euleros 2_0_sp13 | — | Upgrade python3-perfUpgrade bpftoolUpgrade kernel-toolsUpgrade kernel-abi-stablelistsUpgrade kernel-tools-libsUpgrade kernel | Mar 10, 2026 | Mar 10, 2026 |
| Redhat_linux | — | No solution exists | Jul 17, 2026 | Oct 1, 2025 |
| Ubuntu | — | Upgrade linux-nvidia-tegraUpgrade linuxUpgrade linux-gkeopUpgrade linux-gkeUpgrade linux-intel-iot-realtimeUpgrade linux-awsUpgrade linux-ibm-5.15Upgrade linux-nvidia-tegra-5.15Upgrade linux-nvidia-tegra-igxUpgrade linux-lowlatencyUpgrade linux-nvidiaUpgrade linux-realtimeUpgrade linux-lowlatency-hwe-5.15Upgrade linux-azure-5.15Upgrade linux-gcp-5.15Upgrade linux-xilinx-zynqmpUpgrade linux-oracleUpgrade linux-kvmUpgrade linux-ibmUpgrade linux-oracle-5.15Upgrade linux-aws-5.15Upgrade linux-raspiUpgrade linux-riscv-5.15Upgrade linux-bluefieldUpgrade linux-azureUpgrade linux-intel-iotgUpgrade linux-intel-iotg-5.15Upgrade linux-gcpUpgrade linux-hwe-5.15Upgrade linux-azure-fde | Oct 10, 2025 | Oct 1, 2025 |
| Vmware Photon_os | — | Use 'tdnf update' to upgrade all packages to the latest version. | Oct 15, 2025 | Oct 1, 2025 |
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