CVE-2026-53240

In the Linux kernel, the following vulnerability has been resolved: xfrm: iptfs: fix use-after-free on first_skb in __input_process_payload __input_process_payload() stores first_skb into xtfs->ra_newskb under drop_lock when starting partial reassembly, then unlocks and breaks out of the processing loop. The post-loop check reads xtfs->ra_newskb without the lock to decide whether first_skb is still owned: if (first_skb && first_iplen && !defer && first_skb != xtfs->ra_newskb) Between spin_unlock and this read, a concurrent CPU running iptfs_reassem_cont() (or the drop_timer hrtimer) can complete reassembly, NULL xtfs->ra_newskb, and free the skb. The check then evaluates first_skb != NULL as true, and pskb_trim/ip_summed/consume_skb operate on the freed skb — a use-after-free in skbuff_head_cache. Replace the unlocked read with a local bool that records whether first_skb was handed to the reassembly state in the current call. The flag is set after the existing spin_unlock, before the break, using the pointer equality that is stable at that point (first_skb == skb iff first_skb was stored in ra_newskb).

Affected products

Kernel, Linux, Linux-Allwinner-5.19, Linux-Aws, Linux-Aws-5.0, Linux-Aws-5.11, Linux-Aws-5.13, Linux-Aws-5.19

Linux Linux Kernel

< 6.18.36, 7.0.13, 7.1

CVSS 3.1

8.8 HIGH

EPSS

0.4% (32th percentile)

Weakness

CWE-416

NVD status

Analyzed

Published

2026-06-25

No exploit for CVE-2026-53240 has been indexed yet. Our index is built from live traffic and upstream syncs, so this page can only say what it knows — not that no exploit exists.