CVE-2025-37749 Information

Description

In the Linux kernel the following vulnerability has been resolved:

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

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 ppp_sync_txmung receives an incoming package with an empty payload: (remote) gef? p (struct pppoe_hdr ) (skb->head + skb->network_header) $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\n data = 0xffff88803346f416 :\377\n truesize = 0x380 len = 0x0 data_len = 0x0 mac_len = 0xe hdr_len = 0x0

it is not safe to access data[2].

[pabeni@redhat.com: fixed subj typo]

Reference

https://git.kernel.org/stable/c/1f6eb9fa87a781d5370c0de7794ae242f1a95ee5 https://git.kernel.org/stable/c/6e8a6bf43cea4347121ab21bb1ed8d7bef7e732e https://git.kernel.org/stable/c/aabc6596ffb377c4c9c8f335124b92ea282c9821 https://git.kernel.org/stable/c/b4c836d33ca888695b2f2665f948bc1b34fbd533 https://git.kernel.org/stable/c/b78f2b458f56a5a4d976c8e01c43dbf58d3ea2ca https://git.kernel.org/stable/c/fbaffe8bccf148ece8ad67eb5d7aa852cabf59c8