CVE-2026-68426
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.
CSIRTS triage
- What
- Stale pointer in skb->prev after asynchronous crypto steals a GSO segment, leading to memory corruption.
- Who is affected
- Systems running Linux kernel with xfrm (IPsec) and GSO (Generic Segmentation Offload) enabled.
- Urgency
- Moderate urgency; CVSS 4.7 indicates denial of service or limited memory corruption risk.
- Action
- Apply Linux kernel patch fixing skb->prev state after async crypto GSO segment theft.
AI-assisted analysis generated from the source advisory — verify against the original.
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Exploitation outlook
- Low exploitation risk0.37% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 30% of all EPSS-scored CVEs.
Advisory coverage (2)
External references
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