CVE-2025-37749

In the Linux kernel, the following vulnerability has been resolved:

net: ppp: Add bound checking for skb data on pppsynctxmung

Ensure we have enough data in linear buffer from skb before accessing initial bytes. This prevents potential out-of-bounds accesses when processing short packets.

When pppsynctxmung receives an incoming package with an empty payload: (remote) gef➤ p *(struct pppoehdr *) (skb->head + skb->networkheader) $18 = { type = 0x1, ver = 0x1, code = 0x0, sid = 0x2, length = 0x0, tag = 0xffff8880371cdb96 }

from the skb struct (trimmed) tail = 0x16, end = 0x140, head = 0xffff88803346f400 "4", data = 0xffff88803346f416 ":\377", truesize = 0x380, len = 0x0, datalen = 0x0, maclen = 0xe, hdr_len = 0x0,

it is not safe to access data[2].

[pabeni@redhat.com: fixed subj typo]