CVE-2025-37749 net: ppp: Add bound checking for skb data on ppp_sync_txmung
A missing bounds check in the Linux kernel PPP driver allows out-of-bounds access when processing short packets, potentially leading to crashes or code execution.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-37749?
CVE-2025-37749 is a high-severity memory corruption vulnerability in Debian Debian Linux, published on 1 May 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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", data = 0xffff88803346f416 ":\377", truesize = 0x380, len = 0x0, data_len = 0x0, mac_len = 0xe, hdr_len = 0x0,
it is not safe to access data[2].
[[email protected]: fixed subj typo]
Weakness: CWE-125
Which versions are affected by CVE-2025-37749?
It affects 2 products.
Products include Debian Debian Linux, Linux kernel.
How do I fix CVE-2025-37749?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2025-37749 being exploited?
There is no known exploitation of CVE-2025-37749 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as BELL-CVE-2025-37749, DEBIAN-CVE-2025-37749, GHSA-v3g9-9rfh-r7cr, ROOT-OS-DEBIAN-12-CVE-2025-37749, ROOT-OS-UBUNTU-2204-CVE-2025-37749, ROOT-OS-UBUNTU-2404-CVE-2025-37749 and 1 more.