CVE-2026-31469
HighCVSS 7.8Exploitation Probability (EPSS)
Low risk8th percentile - higher than 8% of all known CVEs
Summary
A use-after-free (UAF) vulnerability in the dst_ops structure was found in the Linux kernel's virtio_net driver. It occurs when IFF_XMIT_DST_RELEASE is cleared and napi_tx is disabled, leading to freed memory access during transmit buffer cleanup.
Risk Assessment
An attacker could exploit this vulnerability to cause a kernel panic or potentially escalate privileges by destroying network namespaces while packets are pending in the transmit ring.
Recommendation
Immediately update the Linux kernel to a version containing the fix (commit adding skb_dst_drop in start_xmit). If an update is not possible, temporarily disable tc route filter or set napi_tx=Y.
Other vulnerabilities in Linux kernel
See all- CVE-2026-99282Unknown
In the Linux kernel, net/sched: sch_teql contains a use-after-free vulnerability. teql_master_xmit() incorrectly treats NET_XMIT_DROP as an unconsumed packet and operates on freed memory. The issue affects configurations with VLAN interfaces and pfifo qdisc with limit 0.
- CVE-2026-99281Unknown
A flaw in the Linux kernel tun/tap mechanism allowed processes without CAP_NET_ADMIN to attach to persistent tun devices that had no owner or group set. Anyone able to open /dev/net/tun could attach to such devices and intercept or inject network traffic. The fix now requires CAP_NET_ADMIN to attach to an ownerless, groupless device.
- CVE-2026-99280Unknown
In the Linux kernel, the following vulnerability has been resolved: ksmbd: drain session procfs readers before dropping table references. Session registration failure and connection cleanup can drop the table reference while the per-session procfs entry is still accessible. If a reader holds the last remaining reference, its final put calls proc_remove() from its own callback and waits for that callback to finish. Remove the procfs entry before dropping the table reference in the registration failure path. Queue sessions removed during connection cleanup and drain their procfs readers after releasing both session locks, then return their table references. Keep the global hash node unhashed while a session is queued so a concurrent unregister cannot drop the reference again. Previous-session replacement also destroys the file table before the session is finally freed. Detach the idr under the lock used by procfs file counters, and report zero files after it has been detached. This prevents a reader from accessing the idr during or after its destruction.
- CVE-2026-99278Unknown
In the Linux kernel, the following vulnerability has been resolved: ksmbd: limit sessions on each connection. The pending setup limit only counts InProgress sessions. A client can complete authentication repeatedly and retain an unbounded number of Valid sessions on one connection. Reserve a connection slot before allocating a session and retain a connection reference while authentication is in progress. The first SMB3 channel takes over that reservation; binding to another connection reserves one slot there. Reauthentication and authentication continuation reuse the existing reservation. Return slots on allocation or insertion failure, channel removal, and final session destruction. Accept max_sessions_per_connection in reserved startup-request space and default to 64 when older tools leave it zero. Keep the request size and existing field offsets unchanged. Expose the configured limit in procfs. The existing connection limits bound the aggregate number of sessions without a separate global session allocation limit.
- CVE-2026-99259Unknown
In the Linux kernel, the soc/tegra: pmc driver has an uninitialised early_pmc->rate variable for legacy 32-bit Tegra devices. The variable is never configured and remains 0, triggering a warning in tegra_pmc_enter_suspend_mode(). The issue appeared after the PMC driver was changed to create the PMC context dynamically, updating rate only in the new context.
- CVE-2026-99258Unknown
In the Linux kernel, hv_apicid_to_vp_index() uses per-CPU hypercall input and output pages. In an SEV-SNP CoCo VM without a paravisor the output page is not allocated, so the hypervisor stores the resulting VP index into memory not allocated by the guest. The fix uses the input page for both input and output.
- CVE-2026-99257Unknown
In the Linux kernel, the shared GPIO mechanism based on platform lookup tables requires an associated struct device. An fwnode-based lookup with no associated device currently causes a NULL-pointer dereference. The fix adds a check that lets the kernel gracefully handle this situation with an error.
- CVE-2026-99256Unknown
In the Linux kernel, the dm cache module used a rw_semaphore for background_work_lock, although write locks on rw_semaphores have strict owner semantics. The locking process was not always the same as the unlocking one, triggering a warning with CONFIG_DEBUG_RWSEMS during suspend/resume of a cache device. The fix replaces the rw_semaphore with a spinlock and a wait queue.
- CVE-2026-99251Unknown
In the Linux kernel, init_vp_index() contains a retry loop that strips CPUs from a node if they are already in the allocated cpumask or outside the HK_TYPE_MANAGED_IRQ housekeeping cpumask. If the housekeeping cpumask contains no CPU in that node, the loop becomes infinite. The fix skips NUMA nodes with no housekeeping CPU and aborts early when no online housekeeping CPUs exist.
- CVE-2026-99250Unknown
In the Linux kernel, the NBCON console printing kthreads are started very early during boot via early_initcall(). Asynchronously enabling/disabling interrupts during early boot may interfere with early SMP setup on some hardware platforms, causing hangs. The fix postpones kthread startup until after all arch initcalls have completed.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: virtio_net: Fix UAF on dst_ops when IFF_XMIT_DST_RELEASE is cleared and napi_tx is false A UAF issue occurs when the virtio_net driver is configured with napi_tx=N and the device's IFF_XMIT_DST_RELEASE flag is cleared (e.g., during the configuration of tc route filter rules). When IFF_XMIT_DST_RELEASE is removed from the net_device, the network stack expects the driver to hold the reference to skb->dst until the packet is fully transmitted and freed. In virtio_net with napi_tx=N, skbs may remain in the virtio transmit ring for an extended period. If the network namespace is destroyed while these skbs are still pending, the corresponding dst_ops structure has freed. When a subsequent packet is transmitted, free_old_xmit() is triggered to clean up old skbs. It then calls dst_release() on the skb associated with the stale dst_entry. Since the dst_ops (referenced by the dst_entry) has already been freed, a UAF kernel paging request occurs. fix it by adds skb_dst_drop(skb) in start_xmit to explicitly release the dst reference before the skb is queued in virtio_net. Call Trace: Unable to handle kernel paging request at virtual address ffff80007e150000 CPU: 2 UID: 0 PID: 6236 Comm: ping Kdump: loaded Not tainted 7.0.0-rc1+ #6 PREEMPT ... percpu_counter_add_batch+0x3c/0x158 lib/percpu_counter.c:98 (P) dst_release+0xe0/0x110 net/core/dst.c:177 skb_release_head_state+0xe8/0x108 net/core/skbuff.c:1177 sk_skb_reason_drop+0x54/0x2d8 net/core/skbuff.c:1255 dev_kfree_skb_any_reason+0x64/0x78 net/core/dev.c:3469 napi_consume_skb+0x1c4/0x3a0 net/core/skbuff.c:1527 __free_old_xmit+0x164/0x230 drivers/net/virtio_net.c:611 [virtio_net] free_old_xmit drivers/net/virtio_net.c:1081 [virtio_net] start_xmit+0x7c/0x530 drivers/net/virtio_net.c:3329 [virtio_net] ... Reproduction Steps: NETDEV="enp3s0" config_qdisc_route_filter() { tc qdisc del dev $NETDEV root tc qdisc add dev $NETDEV root handle 1: prio tc filter add dev $NETDEV parent 1:0 \ protocol ip prio 100 route to 100 flowid 1:1 ip route add 192.168.1.100/32 dev $NETDEV realm 100 } test_ns() { ip netns add testns ip link set $NETDEV netns testns ip netns exec testns ifconfig $NETDEV 10.0.32.46/24 ip netns exec testns ping -c 1 10.0.32.1 ip netns del testns } config_qdisc_route_filter test_ns sleep 2 test_ns
Vulnerability data from NVD (NIST) · CISA KEV · EPSS

