CVE-2023-53338

Description

In the Linux kernel, the following vulnerability has been resolved: lwt: Fix return values of BPF xmit ops BPF encap ops can return different types of positive values, such like NET_RX_DROP, NET_XMIT_CN, NETDEV_TX_BUSY, and so on, from function skb_do_redirect and bpf_lwt_xmit_reroute. At the xmit hook, such return values would be treated implicitly as LWTUNNEL_XMIT_CONTINUE in ip(6)_finish_output2. When this happens, skbs that have been freed would continue to the neighbor subsystem, causing use-after-free bug and kernel crashes. To fix the incorrect behavior, skb_do_redirect return values can be simply discarded, the same as tc-egress behavior. On the other hand, bpf_lwt_xmit_reroute returns useful errors to local senders, e.g. PMTU information. Thus convert its return values to avoid the conflict with LWTUNNEL_XMIT_CONTINUE.

PUBLISHED Reserved 2025-09-16 | Published 2025-09-17 | Updated 2025-09-17 | Assigner Linux

Product status

References

git.kernel.org/...c/67f8f2bae8e7ac72e09def2b667e44704c4d1ee1

git.kernel.org/...c/a97f221651fcdc891166e9bc270e3d9bfa5a0080

git.kernel.org/...c/e3f647e4b642f9f6d32795a16f92c116c138d2af

git.kernel.org/...c/065d5f17096ec9161180e2c890afdff4dc6125f2

git.kernel.org/...c/d68c17402442f5f494a2c3ebde5cb82f6aa9160a

git.kernel.org/...c/65583f9e070db7bece20710cfa2e3daeb0b831d9

git.kernel.org/...c/29b22badb7a84b783e3a4fffca16f7768fb31205

cve.org (CVE-2023-53338)

nvd.nist.gov (CVE-2023-53338)

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