CVE-2024-49948 net: add more sanity checks to qdisc_pkt_len_init()
A malicious GSO packet can cause an integer underflow in the Linux kernel's qdisc packet length initialization, potentially leading to a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2024-49948?
CVE-2024-49948 is a medium-severity vulnerability in Linux kernel, published on 21 Oct 2024. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
net: add more sanity checks to qdisc_pkt_len_init()
One path takes care of SKB_GSO_DODGY, assuming skb->len is bigger than hdr_len.
virtio_net_hdr_to_skb() does not fully dissect TCP headers, it only make sure it is at least 20 bytes.
It is possible for an user to provide a malicious 'GSO' packet, total length of 80 bytes.
- 20 bytes of IPv4 header - 60 bytes TCP header - a small gso_size like 8
virtio_net_hdr_to_skb() would declare this packet as a normal GSO packet, because it would see 40 bytes of payload, bigger than gso_size.
We need to make detect this case to not underflow qdisc_skb_cb(skb)->pkt_len.
Which versions are affected by CVE-2024-49948?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2024-49948?
Apply the vendor's patch.
Is CVE-2024-49948 being exploited?
There is no known exploitation of CVE-2024-49948 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-52620, BELL-CVE-2024-49948, DEBIAN-CVE-2024-49948, GHSA-rxhv-mw63-w89c, UBUNTU-CVE-2024-49948.