CVE-2026-68296
Description
In the Linux kernel, the following vulnerability has been resolved:
net: gre: fix lltx regression for GRE tunnels with SEQ/CSUM
Before commit 00d066a4d4ed ('netdev_features: convert NETIF_F_LLTX to
dev->lltx'), NETIF_F_LLTX was set unconditionally in both
__gre_tunnel_init() and ip6gre_tnl_init_features() alongside
GRE_FEATURES:
dev->features |= GRE_FEATURES | NETIF_F_LLTX;
When that commit converted NETIF_F_LLTX to the dev->lltx flag, it
placed 'dev->lltx = true' after the SEQ/CSUM early returns instead
of before them. This causes GRE/GRETAP/ip6gre tunnels with SEQ or
CSUM+encap to lose lockless TX, reintroducing _xmit_lock acquisition
around their ndo_start_xmit. Since GRE xmit re-enters the stack via
ip_tunnel_xmit(), holding _xmit_lock risks ABBA deadlock with the
underlay device.
CPU0 CPU1
---- ----
lock(&qdisc_xmit_lock_key#6);
lock(&qdisc_xmit_lock_key#3);
lock(&qdisc_xmit_lock_key#6);
lock(&qdisc_xmit_lock_key#3);
Fix by moving dev->lltx = true before the early returns in both
functions, restoring the original unconditional behavior.
EPSS (Exploit Prediction Scoring System)
EPSS (Exploit Prediction Scoring System)
Prevede la probabilità di sfruttamento basata su intelligence sulle minacce e sulle caratteristiche della vulnerabilità.
Single Data Point
Only one EPSS measurement is available for this CVE. Trend analysis requires multiple data points over time.