Discovery API Icon
Discovery API
Security Advisory Icon
Security Advisory
Package Manager Icon
Package Manager
Alpaquita LinuxStreamSecurity Advisory
Search Cve

CVE-2026-63829

Published: July 22, 2026Last modified: August 14, 2026

Description

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.

Severity score breakdown

ParameterValue
Base score8.8
Attack VectorLOCAL
Attack complexityLOW
Privileges requiredLOW
User interactionNONE
ScopeCHANGED
ConfidentialityHIGH
Integrity impactHIGH
Availability impactHIGH
VectorCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Status

ProductReleasePackageStatus
Alpaquita Linux23 LTSlinux-ltsFixed (6.1.182-r0)
25 LTSlinux-ltsFixed (6.12.95-r0)
Streamlinux-ltsFixed (6.18.38-r0)

References

ON THIS PAGE