CVE-2026-97602

Status: UPDATED  |  Advisory ID: CVE-2026-97602

Key Details

Affected Products, Subsystems & Sectors

What to Know

In the Linux kernel, the following vulnerability has been resolved:

inet: frags: invalidate queues before flushing them

fqdir_pre_exit() flushes the skbs from incomplete queues without

changing their completion state. A fragment which found a queue before

high_thresh was cleared can then acquire the queue lock and reuse stale

reassembly metadata. A queue concurrently killed after fqdir->dead is

set can instead become INET_FRAG_COMPLETE|INET_FRAG_HASH_DEAD while

still holding its old skbs; skipping it because it is complete leaves

those references behind until asynchronous fqdir teardown.

For IPv6, stale metadata can make ip6_frag_reasm() use the old

nhoffset with a new skb and access memory out of bounds. The resulting

heap corruption can be leveraged for local privilege escalation when

unprivileged network namespaces are available. Unflushed fragments can

also keep conntrack references alive after the conntrack per-net

cleanup point.

Kill each incomplete queue, then flush every queue still owned by the

dying rhashtable. HASH_DEAD identifies that ownership, while complete

queues without it are already owned by another destroy path and must be

left alone. Releasing a timer reference removed by inet_frag_kill() is

deferred to inet_frag_putn(), after the queue lock is dropped.

KASAN report:

BUG: KASAN: slab-out-of-bounds in ipv6_frag_rcv (net/ipv6/reassembly.c:289 (discriminator 2) net/ipv6/reassembly.c:229 (discriminator 2) net/ipv6/reassembly.c:391 (discriminator 2))

Write of size 1 at addr ff110001039c6e00 by task poc/771

Call Trace:

? ipv6_frag_rcv (net/ipv6/reassembly.c:289 (discriminator 2) net/ipv6/reassembly.c:229 (discriminator 2) net/ipv6/reassembly.c:391 (discriminator 2))

ipv6_frag_rcv (net/ipv6/reassembly.c:289 (discriminator 2) net/ipv6/reassembly.c:229 (discriminator 2) net/ipv6/reassembly.c:391 (discriminator 2))

ip6_protocol_deliver_rcu (net/ipv6/ip6_input.c:479 (discriminator 5))

ip6_input_finish (net/ipv6/ip6_input.c:534)

ipv6_rcv (include/net/dst.h:480 (discriminator 3) net/ipv6/ip6_input.c:119 (discriminator 3) net/ipv6/ip6_input.c:109 (discriminator 3) include/linux/netfilter.h:325 (discriminator 3) include/linux/netfilter.h:319 (discriminator 3) net/ipv6/ip6_input.c:351 (discriminator 3))

packet_sendmsg (net/packet/af_packet.c:3110 net/packet/af_packet.c:3142)

__x64_sys_sendmmsg (net/socket.c:2883 net/socket.c:2880 net/socket.c:2880)

The buggy address belongs to the object at ff110001039c6b40

which belongs to the cache skbuff_small_head of size 704

The buggy address is located 0 bytes to the right of

allocated 704-byte region [ff110001039c6b40, ff110001039c6e00)

BUG: KASAN: slab-out-of-bounds in ip6_protocol_deliver_rcu (net/ipv6/ip6_input.c:423 (discriminator 1))

Read of size 1 at addr ff110001039c6e08 by task poc/771

Call Trace:

? ip6_protocol_deliver_rcu (net/ipv6/ip6_input.c:423 (discriminator 1))

ip6_protocol_deliver_rcu (net/ipv6/ip6_input.c:423 (discriminator 1))

ip6_input_finish (net/ipv6/ip6_input.c:534)

ipv6_rcv (include/net/dst.h:480 (discriminator 3) net/ipv6/ip6_input.c:119 (discriminator 3) net/ipv6/ip6_input.c:109 (discriminator 3) include/linux/netfilter.h:325 (discriminator 3) include/linux/netfilter.h:319 (discriminator 3) net/ipv6/ip6_input.c:351 (discriminator 3))

packet_sendmsg (net/packet/af_packet.c:3110 net/packet/af_packet.c:3142)

__x64_sys_sendmmsg (net/socket.c:2883 net/socket.c:2880 net/socket.c:2880)

packet_sendmsg (net/packet/af_packet.c:2959 net/packet/af_packet.c:3053 net/packet/af_packet.c:3142)

__x64_sys_sendmmsg (net/socket.c:2883 net/socket.c:2880 net/socket.c:2880)

The buggy address belongs to the object at ff110001039c6b40

which belongs to the cache skbuff_small_head of size 704

The buggy address is located 8 bytes to the right of

allocated 704-byte region [ff110001039c6b40, ff110001039c6e00) (NVD)

What to Do

Monitor Linux's web page for any future patch releases.

References