CVE-2026-53212

Summary

In the Linux kernel, the following vulnerability has been resolved:

netfilter: nft_tunnel: fix use-after-free on object destroy

nft_tunnel_obj_destroy() calls metadata_dst_free() which directly kfree()s the metadata_dst, ignoring the dst_entry refcount. Packets that took a reference via dst_hold() in nft_tunnel_obj_eval() and are still queued (e.g. in a netem qdisc) are left with a dangling pointer. When these packets are eventually dequeued, dst_release() operates on freed memory.

Replace metadata_dst_free() with dst_release() so the metadata_dst is freed only after all references are dropped. The dst subsystem already handles metadata_dst cleanup in dst_destroy() when DST_METADATA is set.

Affected Software

VendorProductVersion RangeStatus
LinuxLinuxaf308b94a2a4a5a27bec9028354c4df444a7c8ba < 349df61526d2e39decc685d246202e3e284cfe05affected
LinuxLinuxaf308b94a2a4a5a27bec9028354c4df444a7c8ba < 55b79b1ae42372012413ce0413181d26679b17efaffected
LinuxLinuxaf308b94a2a4a5a27bec9028354c4df444a7c8ba < 5e9ee18b27fde88cb6148202b33916c66693fe82affected
LinuxLinuxaf308b94a2a4a5a27bec9028354c4df444a7c8ba < 8767fe4079affa74314d7eb3220e700150289842affected
LinuxLinuxaf308b94a2a4a5a27bec9028354c4df444a7c8ba < fda6573a46ad24f35348e024905ee5bdf729797eaffected
LinuxLinuxaf308b94a2a4a5a27bec9028354c4df444a7c8ba < 941d7394efda5e054e2d6f3e0dd0f6a9ba19aaa3affected
LinuxLinuxaf308b94a2a4a5a27bec9028354c4df444a7c8ba < f9a0e4b61054cde89a2a77845293c726cc07cc43affected
LinuxLinuxaf308b94a2a4a5a27bec9028354c4df444a7c8ba < c32b26aaa2f9216520a38b3f4bfeec846eb3eb8aaffected
LinuxLinux4.19affected
LinuxLinux0 < 4.19unaffected
LinuxLinux5.10.259 <= 5.10.*unaffected
LinuxLinux5.15.210 <= 5.15.*unaffected
LinuxLinux6.1.176 <= 6.1.*unaffected
LinuxLinux6.6.143 <= 6.6.*unaffected
LinuxLinux6.12.94 <= 6.12.*unaffected
LinuxLinux6.18.36 <= 6.18.*unaffected
LinuxLinux7.0.13 <= 7.0.*unaffected
LinuxLinux7.1 <= *unaffected

Weaknesses

References