CVE-2021-47162

In the Linux kernel, the following vulnerability has been resolved: tipc: skb_linearize the head skb when reassembling msgs It's not a good idea to append the frag skb to a skb's frag_list if the frag_list already has skbs from elsewhere, such as this skb was created by pskb_copy() where the frag_list was cloned (all the skbs in it were skb_get'ed) and shared by multiple skbs. However, the new appended frag skb should have been only seen by the current skb. Otherwise, it will cause use after free crashes as this appended frag skb are seen by multiple skbs but it only got skb_get called once. The same thing happens with a skb updated by pskb_may_pull() with a skb_cloned skb. Li Shuang has reported quite a few crashes caused by this when doing testing over macvlan devices: [] kernel BUG at net/core/skbuff.c:1970! [] Call Trace: [] skb_clone+0x4d/0xb0 [] macvlan_broadcast+0xd8/0x160 [macvlan] [] macvlan_process_broadcast+0x148/0x150 [macvlan] [] process_one_work+0x1a7/0x360 [] worker_thread+0x30/0x390 [] kernel BUG at mm/usercopy.c:102! [] Call Trace: [] __check_heap_object+0xd3/0x100 [] __check_object_size+0xff/0x16b [] simple_copy_to_iter+0x1c/0x30 [] __skb_datagram_iter+0x7d/0x310 [] __skb_datagram_iter+0x2a5/0x310 [] skb_copy_datagram_iter+0x3b/0x90 [] tipc_recvmsg+0x14a/0x3a0 [tipc] [] ____sys_recvmsg+0x91/0x150 [] ___sys_recvmsg+0x7b/0xc0 [] kernel BUG at mm/slub.c:305! [] Call Trace: [] <IRQ> [] kmem_cache_free+0x3ff/0x400 [] __netif_receive_skb_core+0x12c/0xc40 [] ? kmem_cache_alloc+0x12e/0x270 [] netif_receive_skb_internal+0x3d/0xb0 [] ? get_rx_page_info+0x8e/0xa0 [be2net] [] be_poll+0x6ef/0xd00 [be2net] [] ? irq_exit+0x4f/0x100 [] net_rx_action+0x149/0x3b0 ... This patch is to fix it by linearizing the head skb if it has frag_list set in tipc_buf_append(). Note that we choose to do this before calling skb_unshare(), as __skb_linearize() will avoid skb_copy(). Also, we can not just drop the frag_list either as the early time.

• CWE-416

• https://git.kernel.org/stable/c/436d650d374329a591c30339a91fa5078052ed1ePatch
• https://git.kernel.org/stable/c/4b1761898861117c97066aea6c58f68a7787f0bfPatch
• https://git.kernel.org/stable/c/5489f30bb78ff0dafb4229a69632afc2ba20765cPatch
• https://git.kernel.org/stable/c/64d17ec9f1ded042c4b188d15734f33486ed9966Patch
• https://git.kernel.org/stable/c/6da24cfc83ba4f97ea44fc7ae9999a006101755cPatch
• https://git.kernel.org/stable/c/ace300eecbccaa698e2b472843c74a5f33f7dce8Patch
• https://git.kernel.org/stable/c/b2c8d28c34b3070407cb1741f9ba3f15d0284b8bPatch
• https://git.kernel.org/stable/c/b7df21cf1b79ab7026f545e7bf837bd5750ac026Patch
• https://git.kernel.org/stable/c/436d650d374329a591c30339a91fa5078052ed1ePatch
• https://git.kernel.org/stable/c/4b1761898861117c97066aea6c58f68a7787f0bfPatch
• https://git.kernel.org/stable/c/5489f30bb78ff0dafb4229a69632afc2ba20765cPatch
• https://git.kernel.org/stable/c/64d17ec9f1ded042c4b188d15734f33486ed9966Patch
• https://git.kernel.org/stable/c/6da24cfc83ba4f97ea44fc7ae9999a006101755cPatch
• https://git.kernel.org/stable/c/ace300eecbccaa698e2b472843c74a5f33f7dce8Patch
• https://git.kernel.org/stable/c/b2c8d28c34b3070407cb1741f9ba3f15d0284b8bPatch
• https://git.kernel.org/stable/c/b7df21cf1b79ab7026f545e7bf837bd5750ac026Patch

Published

Mar 25, 2024

Last Modified

Aug 4, 2026

Status

Modified

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
• Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
• PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
• AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.

• CVE-2021-47156The Net::IPAddress::Util module before 5.000 for Perl does n…6.5
• CVE-2021-47157The Kossy module before 0.60 for Perl allows JSON hijacking …9.8
• CVE-2021-47158In the Linux kernel, the following vulnerability has been re…5.5
• CVE-2021-47159In the Linux kernel, the following vulnerability has been re…5.5
• CVE-2021-47160In the Linux kernel, the following vulnerability has been re…7.1
• CVE-2021-47161In the Linux kernel, the following vulnerability has been re…5.5
• CVE-2021-47163In the Linux kernel, the following vulnerability has been re…5.5
• CVE-2021-47164In the Linux kernel, the following vulnerability has been re…5.5
• CVE-2021-47165In the Linux kernel, the following vulnerability has been re…5.5
• CVE-2021-47166In the Linux kernel, the following vulnerability has been re…5.5
• CVE-2021-47167In the Linux kernel, the following vulnerability has been re…5.5
• CVE-2021-47168In the Linux kernel, the following vulnerability has been re…5.5