# CVE-2026-68323: tipc: serialize udp bearer replicast list updates CVE-2026-68323 is fixed in 16 products on 1 platform, first by DEBIAN-CVE-2026-68323, released August 11, 2026. It is not reported as exploited. Patch Radar priority: High. - Web page: https://patchblox.com/security/cve/CVE-2026-68323 - Priority: High - CVSS: 7.8 (Moderate) - EPSS: 0.0010 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Aug 10, 2026 - Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-68323 ## Description In the Linux kernel, the following vulnerability has been resolved: tipc: serialize udp bearer replicast list updates tipc_udp_rcast_add() and cleanup_bearer() both update ub->rcast.list with list_add_rcu() / list_del_rcu(), but nothing serializes them. The add runs from the encap receive softirq (via tipc_udp_rcast_disc()) without rtnl_lock(), so it can race the cleanup delete and corrupt the list: list_del corruption. prev->next should be ffff8880298d7ab8, but was ffff88802449ad38. (prev=ffff888027e3ec98) kernel BUG at lib/list_debug.c:62! RIP: __list_del_entry_valid_or_report+0x17a/0x200 Workqueue: events cleanup_bearer Call Trace: cleanup_bearer (net/tipc/udp_media.c:811) process_one_work (kernel/workqueue.c:3302) worker_thread (kernel/workqueue.c:3466) The bearer can be enabled from an unprivileged user namespace, as the TIPCv2 generic-netlink ops carry no GENL_ADMIN_PERM. Add a spinlock to struct udp_bearer and take it around the list_add_rcu() in tipc_udp_rcast_add() and the list_del_rcu() loop in cleanup_bearer() so the two writers can no longer corrupt the list. Reject a duplicate peer under the same lock before allocating, and remove tipc_udp_is_known_peer(). The old lockless pre-check in tipc_udp_rcast_disc() was racy: two softirqs discovering the same peer could both find it absent and add it twice. cleanup_bearer() runs from a workqueue after tipc_udp_disable() clears the bearer's up bit, so an encap softirq can still reach tipc_udp_rcast_add() and add a peer after cleanup_bearer() has already emptied the list, leaking that entry when the bearer is freed. Mark the bearer disabled under rcast_lock once the list is emptied and refuse further additions. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | dtb-aarch64 opensuse-leap 16.0 | 6.12.0-160000.40.1 | [OPENSUSE-SU-2026:22167-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22167-1.md) | Nov 7, 2026 | | Linux | kernel-64kb opensuse-leap 16.0 | 6.12.0-160000.40.1 | [OPENSUSE-SU-2026:22167-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22167-1.md) | Nov 7, 2026 | | Linux | kernel-64kb sles 15.7 | 6.4.0-150700.53.87.3 | [SUSE-SU-2026:4935-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4935-1.md) | Nov 7, 2026 | | Linux | kernel-64kb sles 16.0 | 6.12.0-160000.40.1 | [SUSE-SU-2026:24446-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24446-1.md) | Nov 7, 2026 | | Linux | kernel-azure opensuse-leap 16.0 | 6.12.0-160000.40.1 | [OPENSUSE-SU-2026:22167-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22167-1.md) | Nov 7, 2026 | | Linux | kernel-azure sles 15.7 | 6.4.0-150700.53.87.3 | [SUSE-SU-2026:4935-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4935-1.md) | Nov 7, 2026 | | Linux | kernel-azure sles 16.0 | 6.12.0-160000.40.1 | [SUSE-SU-2026:24446-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24446-1.md) | Nov 7, 2026 | | Linux | kernel-default opensuse-leap 16.0 | 6.12.0-160000.40.1 | [OPENSUSE-SU-2026:22167-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22167-1.md) | Nov 7, 2026 | | Linux | kernel-default sles 15.7 | 6.4.0-150700.53.87.3 | [SUSE-SU-2026:4935-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4935-1.md) | Nov 7, 2026 | | Linux | kernel-default sles 16.0 | 6.12.0-160000.40.1 | [SUSE-SU-2026:24446-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24446-1.md) | Nov 7, 2026 | | Linux | kernel-default-base opensuse-leap 16.0 | 6.12.0-160000.40.1.160000.2.29 | [OPENSUSE-SU-2026:22167-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22167-1.md) | Nov 7, 2026 | | Linux | kernel-default-base sles 15.7 | 6.4.0-150700.53.87.3.150700.17.49.2 | [SUSE-SU-2026:4935-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4935-1.md) | Nov 7, 2026 | | Linux | kernel-default-base sles 16.0 | 6.12.0-160000.40.1.160000.2.29 | [SUSE-SU-2026:24446-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24446-1.md) | Nov 7, 2026 | | Linux | kernel-docs opensuse-leap 16.0 | 6.12.0-160000.40.1 | [OPENSUSE-SU-2026:22167-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22167-1.md) | Nov 7, 2026 | | Linux | kernel-docs sles 15.7 | 6.4.0-150700.53.87.3 | [SUSE-SU-2026:4935-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4935-1.md) | Nov 7, 2026 | | Linux | kernel-docs sles 16.0 | 6.12.0-160000.40.1 | [SUSE-SU-2026:24446-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24446-1.md) | Nov 7, 2026 | | Linux | kernel-kvmsmall opensuse-leap 16.0 | 6.12.0-160000.40.1 | [OPENSUSE-SU-2026:22167-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22167-1.md) | Nov 7, 2026 | | Linux | kernel-kvmsmall sles 16.0 | 6.12.0-160000.40.1 | [SUSE-SU-2026:24446-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24446-1.md) | Nov 7, 2026 | | Linux | kernel-livepatch-SLE15-SP7-RT_Update_22 sles 15.7 | 1-150700.1.3.1 | [SUSE-SU-2026:4940-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4940-1.md) | Nov 7, 2026 | | Linux | kernel-livepatch-SLE15-SP7_Update_23 sles 15.7 | 1-150700.15.3.2 | [SUSE-SU-2026:4935-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4935-1.md) | Nov 7, 2026 | | Linux | kernel-obs-build opensuse-leap 16.0 | 6.12.0-160000.40.1 | [OPENSUSE-SU-2026:22167-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22167-1.md) | Nov 7, 2026 | | Linux | kernel-obs-build sles 15.7 | 6.4.0-150700.53.87.2 | [SUSE-SU-2026:4935-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4935-1.md) | Nov 7, 2026 | | Linux | kernel-obs-qa opensuse-leap 16.0 | 6.12.0-160000.40.1 | [OPENSUSE-SU-2026:22167-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22167-1.md) | Nov 7, 2026 | | Linux | kernel-obs-qa sles 16.0 | 6.12.0-160000.40.1 | [SUSE-SU-2026:24446-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24446-1.md) | Nov 7, 2026 | | Linux | kernel-rt opensuse-leap 16.0 | 6.12.0-160000.40.1 | [OPENSUSE-SU-2026:22167-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22167-1.md) | Nov 7, 2026 | | Linux | kernel-source opensuse-leap 16.0 | 6.12.0-160000.40.1 | [OPENSUSE-SU-2026:22167-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22167-1.md) | Nov 7, 2026 | | Linux | kernel-source sles 15.7 | 6.4.0-150700.53.87.3 | [SUSE-SU-2026:4935-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4935-1.md) | Nov 7, 2026 | | Linux | kernel-source sles 16.0 | 6.12.0-160000.40.1 | [SUSE-SU-2026:24446-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24446-1.md) | Nov 7, 2026 | | Linux | kernel-syms opensuse-leap 16.0 | 6.12.0-160000.40.1 | [OPENSUSE-SU-2026:22167-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22167-1.md) | Nov 7, 2026 | | Linux | kernel-syms sles 15.7 | 6.4.0-150700.53.87.1 | [SUSE-SU-2026:4935-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4935-1.md) | Nov 7, 2026 | | Linux | kernel-syms sles 16.0 | 6.12.0-160000.40.1 | [SUSE-SU-2026:24446-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24446-1.md) | Nov 7, 2026 | | Linux | kernel-zfcpdump opensuse-leap 16.0 | 6.12.0-160000.40.1 | [OPENSUSE-SU-2026:22167-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22167-1.md) | Nov 7, 2026 | | Linux | kernel-zfcpdump sles 15.7 | 6.4.0-150700.53.87.3 | [SUSE-SU-2026:4935-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4935-1.md) | Nov 7, 2026 | | Linux | kernel-zfcpdump sles 16.0 | 6.12.0-160000.40.1 | [SUSE-SU-2026:24446-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24446-1.md) | Nov 7, 2026 | | Linux | linux Debian 13.5 (trixie) | 6.12.115-2 | [DEBIAN-CVE-2026-68323](https://patchblox.com/security/data/fix/linux/debian-cve-2026-68323.md) | Aug 11, 2026 | | Linux | linux Debian 14 | 7.1.6-1 | [DEBIAN-CVE-2026-68323](https://patchblox.com/security/data/fix/linux/debian-cve-2026-68323.md) | Aug 11, 2026 | --- Data as of 2026-11-08T13:06:02Z UTC. 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