CVE-2026-89562

Summary

In the Linux kernel, the following vulnerability has been resolved:

ip6_gre: fix hardware header length for NBMA tunnels

ip6gre_tnl_link_config_route() accumulates the lower device's hardware header length into dev->hard_header_len whenever header_ops is set. This is incorrect for both users of header_ops.

ip6gretap and ip6erspan have a fixed Ethernet hardware header length. For an NBMA ip6gre tunnel, ip6gre_header() creates only the GRE header, the optional FOU or GUE header, and the outer IPv6 header. The lower device header is headroom needed later, not part of the tunnel device's hardware header.

Keep the lower device header in needed_headroom. Set hard_header_len to the tunnel header length only for ARPHRD_IP6GRE devices with header_ops, and leave the fixed Ethernet header length unchanged for tap and erspan devices.

Affected Software

VendorProductVersion RangeStatus
LinuxLinux832ba596494b2c9eac7760259eff2d8b7dcad0ee < 8bfe746afee38dd6e4348ddcd22d554789dbb9ffaffected
LinuxLinux832ba596494b2c9eac7760259eff2d8b7dcad0ee < b8282668d8fa7c61b80e8e4890729031c291a16caffected
LinuxLinux832ba596494b2c9eac7760259eff2d8b7dcad0ee < 565038b0092f65afe384961c0f548d605bf438b9affected
LinuxLinux832ba596494b2c9eac7760259eff2d8b7dcad0ee < 505b6d296c486ef7d1274f279d4c43a172f63224affected
LinuxLinuxcf3d9717a5271573fa193c4dfa0df856295d5b15affected
LinuxLinux187a6daf5db45adc807c85bbe285319107bed198affected
LinuxLinuxd9897bb66ce989325b4bf4cdbb6a799e4ac878b6affected
LinuxLinux4.19.162 < 4.20affected
LinuxLinux5.4.82 < 5.5affected
LinuxLinux5.9.13 < 5.10affected
LinuxLinux5.10affected
LinuxLinux0 < 5.10unaffected
LinuxLinux6.12.109 <= 6.12.*unaffected
LinuxLinux6.18.50 <= 6.18.*unaffected
LinuxLinux7.2.4 <= 7.2.*unaffected
LinuxLinux7.3-rc1 <= *unaffected

Weaknesses

References