CVE-2023-54112

Published Dec 24, 2025 Modified Apr 15, 2026

Description

In the Linux kernel, the following vulnerability has been resolved: kcm: Fix memory leak in error path of kcm_sendmsg() syzbot reported a memory leak like below: BUG: memory leak unreferenced object 0xffff88810b088c00 (size 240): comm "syz-executor186", pid 5012, jiffies 4294943306 (age 13.680s) hex dump (first 32 bytes): 00 89 08 0b 81 88 ff ff 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<ffffffff83e5d5ff>] __alloc_skb+0x1ef/0x230 net/core/skbuff.c:634 [<ffffffff84606e59>] alloc_skb include/linux/skbuff.h:1289 [inline] [<ffffffff84606e59>] kcm_sendmsg+0x269/0x1050 net/kcm/kcmsock.c:815 [<ffffffff83e479c6>] sock_sendmsg_nosec net/socket.c:725 [inline] [<ffffffff83e479c6>] sock_sendmsg+0x56/0xb0 net/socket.c:748 [<ffffffff83e47f55>] ____sys_sendmsg+0x365/0x470 net/socket.c:2494 [<ffffffff83e4c389>] ___sys_sendmsg+0xc9/0x130 net/socket.c:2548 [<ffffffff83e4c536>] __sys_sendmsg+0xa6/0x120 net/socket.c:2577 [<ffffffff84ad7bb8>] do_syscall_x64 arch/x86/entry/common.c:50 [inline] [<ffffffff84ad7bb8>] do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80 [<ffffffff84c0008b>] entry_SYSCALL_64_after_hwframe+0x63/0xcd In kcm_sendmsg(), kcm_tx_msg(head)->last_skb is used as a cursor to append newly allocated skbs to 'head'. If some bytes are copied, an error occurred, and jumped to out_error label, 'last_skb' is left unmodified. A later kcm_sendmsg() will use an obsoleted 'last_skb' reference, corrupting the 'head' frag_list and causing the leak. This patch fixes this issue by properly updating the last allocated skb in 'last_skb'.

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References

Frequently Asked Questions

What is CVE-2023-54112? +
In the Linux kernel, the following vulnerability has been resolved: kcm: Fix memory leak in error path of kcm_sendmsg() syzbot reported a memory leak like below: BUG: memory leak unreferenced object 0xffff88810b088c00 (size 240): comm "syz-executor186", pid 5012, jiffies 4294943306 (age 13.680s) hex dump (first 32 bytes): 00 89 08 0b 81 88 ff ff 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<ffffffff83e5d5ff>] __alloc_skb+0x1ef/0x230 net/core/skbuff.c:634 [<ffffffff84606e59>] alloc_skb include/linux/skbuff.h:1289 [inline] [<ffffffff84606e59>] kcm_sendmsg+0x269/0x1050 net/kcm/kcmsock.c:815 [<ffffffff83e479c6>] sock_sendmsg_nosec net/socket.c:725 [inline] [<ffffffff83e479c6>] sock_sendmsg+0x56/0xb0 net/socket.c:748 [<ffffffff83e47f55>] ____sys_sendmsg+0x365/0x470 net/socket.c:2494 [<ffffffff83e4c389>] ___sys_sendmsg+0xc9/0x130 net/socket.c:2548 [<ffffffff83e4c536>] __sys_sendmsg+0xa6/0x120 net/socket.c:2577 [<ffffffff84ad7bb8>] do_syscall_x64 arch/x86/entry/common.c:50 [inline] [<ffffffff84ad7bb8>] do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80 [<ffffffff84c0008b>] entry_SYSCALL_64_after_hwframe+0x63/0xcd In kcm_sendmsg(), kcm_tx_msg(head)->last_skb is used as a cursor to append newly allocated skbs to 'head'. If some bytes are copied, an error occurred, and jumped to out_error label, 'last_skb' is left unmodified. A later kcm_sendmsg() will use an obsoleted 'last_skb' reference, corrupting the 'head' frag_list and causing the leak. This patch fixes this issue by properly updating the last allocated skb in 'last_skb'.
How do I check if I'm vulnerable to CVE-2023-54112? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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