CVE-2026-98030 net: dsa: bcm_sf2: bound the CFP rule dump by the caller's buffer size
A local user can cause a kernel crash by triggering a null pointer dereference in the Broadcom SF2 DSA driver via a crafted ethtool ioctl call.
- 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-2026-98030?
CVE-2026-98030 is a high-severity vulnerability in Linux, published on 25 Sep 2026. 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: dsa: bcm_sf2: bound the CFP rule dump by the caller's buffer size
bcm_sf2_cfp_rule_get_all() walks the whole cfp.unique bitmap into rule_locs[] without consulting nfc->rule_cnt, which is how many entries the caller had room for. ETHTOOL_GRXCLSRLALL requires no CAP_NET_ADMIN and the ioctl sizes the buffer from the rule_cnt userspace passes in, so once an admin has installed CFP rules any user can ask for fewer slots than there are rules and run off the end of the allocation. A rule_cnt of 0 leaves the buffer pointer NULL and the walk dereferences it.
Which versions are affected by CVE-2026-98030?
How do I fix CVE-2026-98030?
Apply the vendor's patch.
Is CVE-2026-98030 being exploited?
There is no known exploitation of CVE-2026-98030 in the wild and no public exploit code.
Sources
Also known as AZL-104169, BELL-CVE-2026-98030, DEBIAN-CVE-2026-98030, GHSA-hmh5-2wm8-hhp7, UBUNTU-CVE-2026-98030.