Overview
About vulnerability
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.
Details
- Affected product:
- AlmaLinux 9.2 ESU , Amazon Linux 2 ELS , Debian 10 ELS , Oracle Linux 7 ELS , TuxCare 9.6 ESU , Ubuntu 18.04 ELS , Ubuntu 20.04 ELS
- Affected packages:
- kernel @ 5.14.0 (+6 more)
Fixes
KernelCare state
Live-patch status from KernelCare for each operating system.
| Operating system | Status | Covered kernels |
|---|---|---|
| Amazon Linux 2023 | Planned | — |
| Debian 11 | Released |
37 kernels
|
| Debian 11 cloud | Released |
17 kernels
|
| Debian 12 | Released |
40 kernels
|
| Debian 13 | Released |
10 kernels
|
| Ubuntu 20.04 | Planned | — |
| Ubuntu 22.04 | Planned | — |
| Ubuntu 22.04 AWS | Planned | — |
| Ubuntu 22.04 Azure | Planned | — |
| Ubuntu 24.04 | Planned | — |
| Ubuntu 24.04 AWS | Planned | — |