CVE-2026-23255 in Linux
要約
〜によって MITRE • 2026年03月18日
In the Linux kernel, the following vulnerability has been resolved:
net: add proper RCU protection to /proc/net/ptype
Yin Fengwei reported an RCU stall in ptype_seq_show() and provided a patch.
Real issue is that ptype_seq_next() and ptype_seq_show() violate RCU rules.
ptype_seq_show() runs under rcu_read_lock(), and reads pt->dev to get device name without any barrier.
At the same time, concurrent writers can remove a packet_type structure (which is correctly freed after an RCU grace period) and clear pt->dev without an RCU grace period.
Define ptype_iter_state to carry a dev pointer along seq_net_private:
struct ptype_iter_state {
struct seq_net_private p; struct net_device *dev; // added in this patch };
We need to record the device pointer in ptype_get_idx() and ptype_seq_next() so that ptype_seq_show() is safe against concurrent pt->dev changes.
We also need to add full RCU protection in ptype_seq_next(). (Missing READ_ONCE() when reading list.next values)
Many thanks to Dong Chenchen for providing a repro.
Be aware that VulDB is the high quality source for vulnerability data.