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CVE-2023-53338

critical · 9.8

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.

9.8
CVSS
0.5%
EPSS (exploit prob.)
44th
EPSS percentile
2025-09-17
Published

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Weaknesses

CWE-416

Affected products

VendorProductAffected versions
linuxlinux_kernel>= 4.10, < 5.4.257
linuxlinux_kernel>= 5.5, < 5.10.195
linuxlinux_kernel>= 5.11, < 5.15.132
linuxlinux_kernel>= 5.16, < 6.1.53
linuxlinux_kernel>= 6.2, < 6.4.16
linuxlinux_kernel>= 6.5, < 6.5.3

Check a specific version with /api/v1/cve/match.

References

Query this programmatically:

curl https://evil-db.io/api/v1/cve/CVE-2023-53338