CVE-2026-72326 net/sched: cake: reject overhead values that underflow length
An integer underflow in the Linux kernel CAKE scheduler allows remote attackers to cause denial of service via crafted network packets.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-72326?
CVE-2026-72326 is a vulnerability in Linux, published on 15 Aug 2026. 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/sched: cake: reject overhead values that underflow length
CAKE accepts signed overhead values and stores them in an s16, but the adjusted packet length calculation uses unsigned arithmetic. A negative effective length can therefore wrap to a large value.
Such configurations make rate accounting depend on integer wraparound rather than on the packet size userspace intended to model. A static netlink lower bound is not enough because packets reaching CAKE can be smaller than any reasonable manual-overhead allowance.
Fold the signed overhead adjustment into the existing datapath MPU clamp so negative adjusted lengths are clamped before link-layer framing adjustments.
Which versions are affected by CVE-2026-72326?
How do I fix CVE-2026-72326?
Apply the vendor's patch.
Is CVE-2026-72326 being exploited?
There is no known exploitation of CVE-2026-72326 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-72326, DEBIAN-CVE-2026-72326, GHSA-mqfm-gm6r-72rv, UBUNTU-CVE-2026-72326.