In the Linux kernel, the following vulnerability has been resolved:
sctp: linearize cloned gso packets in sctp_rcv
A cloned head skb still shares these frag skbs in fraglist with the original head skb. It's not safe to access these frag skbs.
syzbot reported two use-of-uninitialized-memory bugs caused by this:
BUG: KMSAN: uninit-value in sctpinqpop+0x15b7/0x1920 net/sctp/inqueue.c:211 sctpinqpop+0x15b7/0x1920 net/sctp/inqueue.c:211 sctpassocbhrcv+0x1a7/0xc50 net/sctp/associola.c:998 sctpinqpush+0x2ef/0x380 net/sctp/inqueue.c:88 sctpbacklogrcv+0x397/0xdb0 net/sctp/input.c:331 skbacklogrcv+0x13b/0x420 include/net/sock.h:1122 _releasesock+0x1da/0x330 net/core/sock.c:3106 releasesock+0x6b/0x250 net/core/sock.c:3660 sctpwaitforconnect+0x487/0x820 net/sctp/socket.c:9360 sctpsendmsgtoasoc+0x1ec1/0x1f00 net/sctp/socket.c:1885 sctpsendmsg+0x32b9/0x4a80 net/sctp/socket.c:2031 inetsendmsg+0x25a/0x280 net/ipv4/afinet.c:851 socksendmsg_nosec net/socket.c:718 [inline]
and
BUG: KMSAN: uninit-value in sctpassocbhrcv+0x34e/0xbc0 net/sctp/associola.c:987 sctpassocbhrcv+0x34e/0xbc0 net/sctp/associola.c:987 sctpinqpush+0x2a3/0x350 net/sctp/inqueue.c:88 sctpbacklogrcv+0x3c7/0xda0 net/sctp/input.c:331 skbacklogrcv+0x142/0x420 include/net/sock.h:1148 _releasesock+0x1d3/0x330 net/core/sock.c:3213 releasesock+0x6b/0x270 net/core/sock.c:3767 sctpwaitforconnect+0x458/0x820 net/sctp/socket.c:9367 sctpsendmsgtoasoc+0x223a/0x2260 net/sctp/socket.c:1886 sctpsendmsg+0x3910/0x49f0 net/sctp/socket.c:2032 inetsendmsg+0x269/0x2a0 net/ipv4/afinet.c:851 socksendmsgnosec net/socket.c:712 [inline]
This patch fixes it by linearizing cloned gso packets in sctp_rcv().
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"digest": {
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"source": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git@d0194e391bb493aa6cec56d177b14df6b29188d5",
"target": {
"file": "net/sctp/input.c",
"function": "sctp_rcv"
},
"id": "CVE-2025-38718-0a8c97f6"
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"file": "net/sctp/input.c"
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"id": "CVE-2025-38718-0f98a9c5"
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"target": {
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"function": "sctp_rcv"
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"id": "CVE-2025-38718-2467d32a"
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"id": "CVE-2025-38718-44ce2280"
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"target": {
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"function": "sctp_rcv"
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"id": "CVE-2025-38718-56742dd3"
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"signature_type": "Line",
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"id": "CVE-2025-38718-59ee881c"
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"digest": {
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},
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}
]