CVE-2026-68426
CriticalCVSS 9.8Exploitation Probability (EPSS)
Low risk6th percentile - higher than 6% of all known CVEs
Summary
In the Linux kernel, the xfrm subsystem has a vulnerability where skb->prev becomes stale after async crypto steals a GSO segment. If the last segment is stolen, the head's ->prev pointer is not updated, leading to a write through a dangling pointer (use-after-free) in validate_xmit_skb_list(). The fix repoints skb->prev at the last retained segment before returning.
Risk Assessment
The vulnerability may lead to memory corruption, potentially causing system crashes or remote code execution in kernel context if an attacker can influence network traffic.
Recommendation
Apply the Linux kernel patch that fixes the stale pointer issue in the xfrm subsystem immediately.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: xfrm: fix stale skb->prev after async crypto steals a GSO segment skb_gso_segment() leaves the segment list head with ->prev pointing at the last segment, an invariant validate_xmit_skb_list() relies on when it sets its tail pointer (tail = skb->prev). When validate_xmit_xfrm() walks a GSO list and some segments are stolen by async crypto (->xmit() returns -EINPROGRESS), those segments are unlinked from the list but the head ->prev is never updated. If the last segment is the one stolen, the returned head still has ->prev pointing at it, even though it is now owned by the crypto engine and may be freed. validate_xmit_skb_list() later does tail->next = skb, writing through that stale pointer -- a use-after-free. Repoint skb->prev at the last retained segment before returning.