CVE-2026-98102

/// Technical description

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

ipv6: mcast: fix RCU list diversion in ip6_mc_del1_src()

When removing a source filter whose count reaches zero, ip6_mc_del1_src()

unlinks psf from pmc->mca_sources. If the filter was previously active,

the code moved psf directly into pmc->mca_tomb by updating psf->sf_next.

Because pmc->mca_sources is traversed locklessly under RCU (e.g. by

ipv6_chk_mcast_addr()), mutating psf->sf_next before a grace period

elapses diverts concurrent readers to the tombstone list. Consequently,

readers miss remaining active sources in pmc->mca_sources and improperly

examine deleted tombstone entries.

Fix this by allocating a new tombstone node for pmc->mca_tomb (as done

in sf_setstate()) and retiring the original psf via kfree_rcu().

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References