Bug 2482614 (CVE-2026-46120)
| Summary: | CVE-2026-46120 kernel: ip6_gre: Use cached t->net in ip6erspan_changelink() | ||
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| Product: | [Other] Security Response | Reporter: | OSIDB Bzimport <bzimport> |
| Component: | vulnerability | Assignee: | Product Security <prodsec-ir-bot> |
| Status: | NEW --- | QA Contact: | |
| Severity: | medium | Docs Contact: | |
| Priority: | medium | ||
| Version: | unspecified | CC: | rhel-process-autobot, watson-tool-maintainers |
| Target Milestone: | --- | Keywords: | Security |
| Target Release: | --- | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | --- | |
| Doc Text: |
A flaw was found in the Linux kernel's ip6_gre module. An unprivileged user could exploit this vulnerability by migrating a network device, causing the ip6erspan_changelink() function to incorrectly handle network namespace references. This error leads to a use-after-free condition when the original network namespace is destroyed, potentially resulting in a kernel bug and system instability or denial of service.
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Story Points: | --- |
| Clone Of: | Environment: | ||
| Last Closed: | Type: | --- | |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
Upstream advisory: https://lore.kernel.org/linux-cve-announce/2026052815-CVE-2026-46120-1a01@gregkh/T This issue has been addressed in the following products: Red Hat Enterprise Linux 8 Via RHSA-2026:57254 https://access.redhat.com/errata/RHSA-2026:57254 This issue has been addressed in the following products: Red Hat Enterprise Linux 8 Via RHSA-2026:57253 https://access.redhat.com/errata/RHSA-2026:57253 This issue has been addressed in the following products: Red Hat Enterprise Linux 9 Via RHSA-2026:57252 https://access.redhat.com/errata/RHSA-2026:57252 This issue has been addressed in the following products: Red Hat Enterprise Linux 10 Via RHSA-2026:61887 https://access.redhat.com/errata/RHSA-2026:61887 This issue has been addressed in the following products: Red Hat Enterprise Linux 10.0 Extended Update Support Via RHSA-2026:62609 https://access.redhat.com/errata/RHSA-2026:62609 This issue has been addressed in the following products: Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On Via RHSA-2026:65710 https://access.redhat.com/errata/RHSA-2026:65710 This issue has been addressed in the following products: Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions Via RHSA-2026:77214 https://access.redhat.com/errata/RHSA-2026:77214 This issue has been addressed in the following products: Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions Via RHSA-2026:77215 https://access.redhat.com/errata/RHSA-2026:77215 |
In the Linux kernel, the following vulnerability has been resolved: ip6_gre: Use cached t->net in ip6erspan_changelink(). After commit 5e72ce3e3980 ("net: ipv6: Use link netns in newlink() of rtnl_link_ops"), ip6erspan_newlink() correctly resolves the per-netns ip6gre hash via link_net. ip6erspan_changelink() was not converted in that series and still uses dev_net(dev), which diverges from the device's creation netns after IFLA_NET_NS_FD migration. This re-inserts the tunnel into the wrong per-netns hash. The original netns keeps a stale entry. When that netns is later destroyed, ip6gre_exit_rtnl_net() walks the stale entry, producing a slab-use-after-free reported by KASAN, followed by a kernel BUG at net/core/dev.c (LIST_POISON1) in unregister_netdevice_many_notify(). Reachable from an unprivileged user namespace (unshare --user --map-root-user --net). ip6gre_changelink() earlier in the same file already uses the cached t->net; only ip6erspan_changelink() has the wrong shape.