# CVE-2026-64119: linux: In the Linux kernel, the following vulnerability has been resolved: l2tp: use list_del_rcu in l2tp_session_unhash A... CVE-2026-64119 is fixed in 14 products on 1 platform, first by DEBIAN-CVE-2026-64119, released July 20, 2026. It is not reported as exploited. Patch Radar priority: Routine. - Web page: https://patchblox.com/security/cve/CVE-2026-64119 - Priority: Routine - CVSS: 5.5 (medium) - EPSS: 0.0012 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Jul 19, 2026 ## Description In the Linux kernel, the following vulnerability has been resolved: l2tp: use list_del_rcu in l2tp_session_unhash An unprivileged local user can pin a host CPU indefinitely in l2tp_session_get_by_ifname() by issuing L2TP_CMD_SESSION_GET on L2TP_ATTR_IFNAME concurrently with L2TP_CMD_SESSION_CREATE and L2TP_CMD_SESSION_DELETE on the same tunnel. All three commands take GENL_UNS_ADMIN_PERM, so CAP_NET_ADMIN in the netns user namespace suffices; on any host that has l2tp_core loaded the trigger is reachable from a standard `unshare -Urn` sandbox. l2tp_session_unhash() removes a session from tunnel->session_list with list_del_init(), but that list is walked by l2tp_session_get_by_ifname() with list_for_each_entry_rcu() under rcu_read_lock_bh(). list_del_init() leaves the deleted entry's next/prev self-pointing; a reader that has loaded the entry and then advances pos->list.next reads &session->list, container_of()s back to the same session, and list_for_each_entry_rcu() never reaches the list head. The CPU stays in strcmp() inside the walker, with BH and preemption disabled, so RCU grace periods on the host stall behind it and the wedged thread cannot be killed (SIGKILL is delivered on syscall return). Use list_del_rcu() to match the existing list_add_rcu() in l2tp_session_register(); the deleted session remains visible to in-flight walkers with consistent next/prev pointers until kfree_rcu() in l2tp_session_free() releases it. tunnel->session_list has exactly one list_del_init() call site; the list_del_init (&session->clist) at l2tp_core.c:533 operates on the per-collision list, which is not walked under RCU. list_empty(&session->list) is not used anywhere in net/l2tp/ after the unhash point, so dropping the post-delete self-init is safe; the fix has no userspace-visible behavior change. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | dtb-aarch64 opensuse-leap 16.0 | 6.12.0-160000.38.1 | [OPENSUSE-SU-2026:21910-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21910-1.md) | Sep 22, 2026 | | Linux | kernel-64kb opensuse-leap 16.0 | 6.12.0-160000.38.1 | [OPENSUSE-SU-2026:21910-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21910-1.md) | Sep 22, 2026 | | Linux | kernel-64kb sles 16.0 | 6.12.0-160000.38.1 | [SUSE-SU-2026:23902-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23902-1.md) | Sep 22, 2026 | | Linux | kernel-azure opensuse-leap 16.0 | 6.12.0-160000.38.1 | [OPENSUSE-SU-2026:21910-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21910-1.md) | Sep 22, 2026 | | Linux | kernel-azure sles 16.0 | 6.12.0-160000.38.1 | [SUSE-SU-2026:23902-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23902-1.md) | Sep 22, 2026 | | Linux | kernel-default opensuse-leap 16.0 | 6.12.0-160000.38.1 | [OPENSUSE-SU-2026:21910-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21910-1.md) | Sep 22, 2026 | | Linux | kernel-default sles 16.0 | 6.12.0-160000.38.1 | [SUSE-SU-2026:23902-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23902-1.md) | Sep 22, 2026 | | Linux | kernel-default-base opensuse-leap 16.0 | 6.12.0-160000.38.1.160000.2.22 | [OPENSUSE-SU-2026:21910-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21910-1.md) | Sep 22, 2026 | | Linux | kernel-default-base sles 16.0 | 6.12.0-160000.38.1.160000.2.23 | [SUSE-SU-2026:23902-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23902-1.md) | Sep 22, 2026 | | Linux | kernel-docs opensuse-leap 16.0 | 6.12.0-160000.38.1 | [OPENSUSE-SU-2026:21910-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21910-1.md) | Sep 22, 2026 | | Linux | kernel-docs sles 16.0 | 6.12.0-160000.38.1 | [SUSE-SU-2026:23902-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23902-1.md) | Sep 22, 2026 | | Linux | kernel-kvmsmall opensuse-leap 16.0 | 6.12.0-160000.38.1 | [OPENSUSE-SU-2026:21910-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21910-1.md) | Sep 22, 2026 | | Linux | kernel-kvmsmall sles 16.0 | 6.12.0-160000.38.1 | [SUSE-SU-2026:23902-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23902-1.md) | Sep 22, 2026 | | Linux | kernel-obs-build opensuse-leap 16.0 | 6.12.0-160000.38.1 | [OPENSUSE-SU-2026:21910-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21910-1.md) | Sep 22, 2026 | | Linux | kernel-obs-qa opensuse-leap 16.0 | 6.12.0-160000.38.1 | [OPENSUSE-SU-2026:21910-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21910-1.md) | Sep 22, 2026 | | Linux | kernel-obs-qa sles 16.0 | 6.12.0-160000.38.1 | [SUSE-SU-2026:23902-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23902-1.md) | Sep 22, 2026 | | Linux | kernel-rt opensuse-leap 16.0 | 6.12.0-160000.38.1 | [OPENSUSE-SU-2026:21910-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21910-1.md) | Sep 22, 2026 | | Linux | kernel-source opensuse-leap 16.0 | 6.12.0-160000.38.1 | [OPENSUSE-SU-2026:21910-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21910-1.md) | Sep 22, 2026 | | Linux | kernel-source sles 16.0 | 6.12.0-160000.38.1 | [SUSE-SU-2026:23902-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23902-1.md) | Sep 22, 2026 | | Linux | kernel-syms opensuse-leap 16.0 | 6.12.0-160000.38.1 | [OPENSUSE-SU-2026:21910-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21910-1.md) | Sep 22, 2026 | | Linux | kernel-syms sles 16.0 | 6.12.0-160000.38.1 | [SUSE-SU-2026:23902-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23902-1.md) | Sep 22, 2026 | | Linux | kernel-zfcpdump opensuse-leap 16.0 | 6.12.0-160000.38.1 | [OPENSUSE-SU-2026:21910-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21910-1.md) | Sep 22, 2026 | | Linux | kernel-zfcpdump sles 16.0 | 6.12.0-160000.38.1 | [SUSE-SU-2026:23902-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23902-1.md) | Sep 22, 2026 | | Linux | linux Debian 13.5 (trixie) | 6.12.94-1 | [DEBIAN-CVE-2026-64119](https://patchblox.com/security/data/fix/linux/debian-cve-2026-64119.md) | Jul 20, 2026 | | Linux | linux Debian 14 | 7.0.12-1 | [DEBIAN-CVE-2026-64119](https://patchblox.com/security/data/fix/linux/debian-cve-2026-64119.md) | Jul 20, 2026 | --- Data as of 2026-11-09T13:31:49Z UTC. 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