--- id: CVE-2026-63829 title: |- In the Linux kernel, the following vulnerability has been resolved: net: ip_gre: require CAP_NET_ADMIN in the device netns for changelink A tunnel changelink() operates on at most two netns, dev_net(dev) and the tunnel link netns t->ne… summary: |- In the Linux kernel, the following vulnerability has been resolved: net: ip_gre: require CAP_NET_ADMIN in the device netns for changelink A tunnel changelink() operates on at most two netns, dev_net(dev) and the tunnel link netns t->ne… severity: high cvss: 8.8 cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H' published: '2026-07-19' updated: '2026-08-17' source: NVD sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-63829' references: - url: 'https://git.kernel.org/stable/c/1697957eb0971d420dde42862b88eb43506a1105' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/19275943d8fe903eb7b9aa53e380e41efd042ada' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/47b5d3d506609b08b2e1f7c14f0b681a1953d572' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/8165f7ff57d9667d2bb477ef6af83ede7fed4ad7' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/866b0f5ae599490bd496fd84581c68ac8b94e6af' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/92b766fc55156e0da2ecd0c2302c971118f8a229' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/9831bc9ecb402957810c2045c663fbfe9b09e296' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/e54c05ed3d9c28733fb9e5837219aca3691defa3' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: >- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-63829.json - url: 'https://access.redhat.com/security/cve/CVE-2026-63829' - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2502230' - url: 'https://www.cve.org/CVERecord?id=CVE-2026-63829' - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-63829' - url: >- https://lore.kernel.org/linux-cve-announce/2026071908-CVE-2026-63829-ff2a@gregkh/T - url: 'https://access.redhat.com/errata/RHSA-2026:76738' - url: 'https://access.redhat.com/errata/RHSA-2026:76739' - url: 'https://access.redhat.com/errata/RHSA-2026:75747' - url: 'https://access.redhat.com/errata/RHSA-2026:75746' tags: - nvd - cve.org - csaf - vex - red-hat epss: 0.00148 epssPercentile: 0.03926 ingestedAt: '2026-08-17T05:47:50.343Z' vendor: Linux product: Linux affected: - >- Linux >= b57708add31494175be741ed3fd24023b50c3423 < 19275943d8fe903eb7b9aa53e380e41efd042ada - >- Linux >= b57708add31494175be741ed3fd24023b50c3423 < 866b0f5ae599490bd496fd84581c68ac8b94e6af - >- Linux >= b57708add31494175be741ed3fd24023b50c3423 < 92b766fc55156e0da2ecd0c2302c971118f8a229 - >- Linux >= b57708add31494175be741ed3fd24023b50c3423 < e54c05ed3d9c28733fb9e5837219aca3691defa3 - >- Linux >= b57708add31494175be741ed3fd24023b50c3423 < 9831bc9ecb402957810c2045c663fbfe9b09e296 - >- Linux >= b57708add31494175be741ed3fd24023b50c3423 < 1697957eb0971d420dde42862b88eb43506a1105 - >- Linux >= b57708add31494175be741ed3fd24023b50c3423 < 47b5d3d506609b08b2e1f7c14f0b681a1953d572 - >- Linux >= b57708add31494175be741ed3fd24023b50c3423 < 8165f7ff57d9667d2bb477ef6af83ede7fed4ad7 - Linux 3.16 ssvc: exploitation: none automatable: 'no' technicalImpact: total timestamp: '2026-10-16T15:31:15.242549Z' patched: - 10base_smtv - enterprise_linux_appstream_v_10 - enterprise_linux_appstream_v_9 - enterprise_linux_baseos_v_10 - enterprise_linux_baseos_v_8 - enterprise_linux_baseos_v_9 - enterprise_linux_codeready_linux_builder_v_10 - enterprise_linux_crb_v_8 - enterprise_linux_codeready_linux_builder_v_9 - enterprise_linux_hidden_v_10 - enterprise_linux_real_time_for_nfv_v_10 - enterprise_linux_nfv_v_8 - enterprise_linux_real_time_for_nfv_v_9 - enterprise_linux_real_time_v_10 - enterprise_linux_rt_v_8 - enterprise_linux_real_time_v_9 cwe: - CWE-266 scores: nvd: 8.8 vendor: 7.8 --- ## Overview In the Linux kernel, the following vulnerability has been resolved: net: ip_gre: require CAP_NET_ADMIN in the device netns for changelink A tunnel changelink() operates on at most two netns, dev_net(dev) and the tunnel link netns t->net. They differ once the device is created in or moved to a netns other than the one the request runs in. The rtnl changelink path checks CAP_NET_ADMIN only against dev_net(dev), so a caller privileged there but not in t->net can rewrite a tunnel that lives in t->net. Add rtnl_dev_link_net_capable() next to rtnl_get_net_ns_capable() in net/core/rtnetlink.c. It requires CAP_NET_ADMIN in the link netns and is skipped when the link netns is dev_net(dev), where the rtnl path already checked it. The other patches in this series use the same helper. Gate ipgre_changelink() and erspan_changelink() with it, at the top of the op before any attribute is parsed, because the parsers update live tunnel fields first. ipgre_netlink_parms() sets t->collect_md before ip_tunnel_changelink() runs. Commit 8b484efd5cb4 ("ip6: vti: Use ip6_tnl.net in vti6_siocdevprivate().") added the same check on the ioctl path. This adds it on RTM_NEWLINK. ## Remediation Refer to the linked advisories for vendor-supplied fixes and affected version ranges. ## Vendor advisories - **RHSA-2026:76738** · Red Hat · fixed in: 10Base-SMTV, Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux BaseOS (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10), Red Hat Enterprise Linux Hidden (v. 10), Red Hat Enterprise Linux Real Time for NFV (v. 10), … · released 2026-10-08 · [advisory](https://access.redhat.com/errata/RHSA-2026:76738) - **RHSA-2026:76739** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux BaseOS (v. 9), Red Hat Enterprise Linux CodeReady Linux Builder (v. 9), Red Hat Enterprise Linux Real Time for NFV (v. 9), Red Hat Enterprise Linux Real Time (v. 9) · released 2026-10-08 · [advisory](https://access.redhat.com/errata/RHSA-2026:76739) - **RHSA-2026:75747** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS (v. 8), Red Hat Enterprise Linux CRB (v. 8) · released 2026-10-05 · [advisory](https://access.redhat.com/errata/RHSA-2026:75747) - **RHSA-2026:75746** · Red Hat · fixed in: Red Hat Enterprise Linux NFV (v. 8), Red Hat Enterprise Linux RT (v. 8) · released 2026-10-05 · [advisory](https://access.redhat.com/errata/RHSA-2026:75746) - **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 9, Red Hat Enterprise Linux 7 · updated 2026-10-26 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-63829.json)