CVE-2026-53363
CriticalCVSS 9.8Exploitation Probability (EPSS)
Low risk22th percentile - higher than 22% of all known CVEs
Summary
In the Linux kernel xfrm iptfs module, iptfs_consume_frags() fails to propagate the SKBFL_SHARED_FRAG flag when transferring fragments between socket buffers. This can lead to incorrect in-place encryption by ESP. A similar bug was fixed in CVE-2026-46300 for skb_try_coalesce().
Risk Assessment
An attacker could exploit this to compromise ESP encryption integrity, potentially allowing decryption or modification of VPN traffic.
Recommendation
Apply the Linux kernel patch that propagates the SKBFL_SHARED_FRAG flag in iptfs_consume_frags() or update the kernel to a fixed version.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: xfrm: iptfs: preserve shared-frag marker in iptfs_consume_frags() iptfs_consume_frags() transfers paged fragments from one socket buffer to another but fails to propagate the SKBFL_SHARED_FRAG flag. This is the same class of bug that was fixed in skb_try_coalesce() for CVE-2026-46300: when fragments backed by read-only page-cache pages are merged, the marker indicating their shared nature must be preserved so that ESP can decide correctly whether in-place encryption is safe. Apply the same two-line fix used in skb_try_coalesce() to iptfs_consume_frags().