CVE-2026-98101

Status: UPDATED  |  Advisory ID: CVE-2026-98101

Key Details

Affected Products, Subsystems & Sectors

What to Know

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

ipv6: mcast: use copy-on-write RCU updates in ip6_mc_source()

pmc->sflist is read locklessly under rcu_read_lock() by

inet6_mc_check() during packet reception in the UDP and RAW

multicast receive paths.

ip6_mc_source() mutated psl->sl_addr and psl->sl_count in-place

when adding or removing a source filter. Additionally, when expanding

the filter buffer, newpsl was published via rcu_assign_pointer()

before writing the new source into the array.

Because 16-byte struct in6_addr writes are not atomic and array

shifting is not synchronized with RCU readers, concurrent readers in

inet6_mc_check() could read torn IPv6 addresses or observe

duplicated/missed source entries.

Fix this by switching ip6_mc_source() to copy-on-write RCU updates:

allocate and fully populate newpsl before publishing it via

rcu_assign_pointer(), and reclaim the old filter via kfree_rcu(),

matching ip6_mc_msfilter().

Also remove the now unused IP6_SFBLOCK macro. (NVD)

What to Do

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

References