← CVE Intelligence

CVE-2026-63829

net: ip_gre: require CAP_NET_ADMIN in the device netns for changelink PUBLISHED

Description (CNA)

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.

Affected (CNA)

Vendor / productVersions
Linux / Linuxaffected b57708add31494175be741ed3fd24023b50c3423 before 19275943d8fe903eb7b9aa53e380e41efd042ada; affected b57708add31494175be741ed3fd24023b50c3423 before 866b0f5ae599490bd496fd84581c68ac8b94e6af; affected b57708add31494175be741ed3fd24023b50c3423 before 92b766fc55156e0da2ecd0c2302c971118f8a229; affected b57708add31494175be741ed3fd24023b50c3423 before e54c05ed3d9c28733fb9e5837219aca3691defa3; affected b57708add31494175be741ed3fd24023b50c3423 before 9831bc9ecb402957810c2045c663fbfe9b09e296; affected b57708add31494175be741ed3fd24023b50c3423 before 1697957eb0971d420dde42862b88eb43506a1105; affected b57708add31494175be741ed3fd24023b50c3423 before 47b5d3d506609b08b2e1f7c14f0b681a1953d572; affected b57708add31494175be741ed3fd24023b50c3423 before 8165f7ff57d9667d2bb477ef6af83ede7fed4ad7
Linux / Linuxaffected 3.16; unaffected 0 before 3.16; unaffected 5.10.261 through 5.10.*; unaffected 5.15.212 through 5.15.*; unaffected 6.1.178 through 6.1.*; unaffected 6.6.145 through 6.6.*; unaffected 6.12.95 through 6.12.*; unaffected 6.18.38 through 6.18.*; unaffected 7.1.3 through 7.1.*; unaffected 7.2 through *

CWE

No CWE identifiers supplied.

References

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.