CVE-2026-98102

Summary

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().

Affected Software

VendorProductVersion RangeStatus
LinuxLinux4b200e398953c237c86d32bf26d4cb2a96556a6f < 4352737297b262e8367675c19a7dc6a9f53c97afaffected
LinuxLinux4b200e398953c237c86d32bf26d4cb2a96556a6f < 8d4fe5c13f5056faa6deb09a90e24a89f9ebfad4affected
LinuxLinux4b200e398953c237c86d32bf26d4cb2a96556a6f < 5149c60c406595b56fda0c6e9aae7fd287f636aaaffected
LinuxLinux4b200e398953c237c86d32bf26d4cb2a96556a6f < 93b49239840b91313adbd77b8b52993eff2d08c1affected
LinuxLinux86c49119f0353f857cc08030ec9e4ebaab3d5a64affected
LinuxLinux5.10.261 < 5.11affected
LinuxLinux5.13affected
LinuxLinux0 < 5.13unaffected
LinuxLinux6.12.111 <= 6.12.*unaffected
LinuxLinux6.18.53 <= 6.18.*unaffected
LinuxLinux7.2.7 <= 7.2.*unaffected
LinuxLinux7.3-rc2 <= *unaffected

Weaknesses

References