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Review reviewHigh

CVE-2023-53338

Linux Linux, linux kernel

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...

CVSS
7.8
EPSS
0.50%
40.2% percentile
CISA KEV
Not listed
Published
2025.09.18
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability0.50%
Technical severityCVSS 7.8

Vulnerability overview

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...

Affected product and versions

Product
Linux Linux, linux kernel
Affected versions
>= 3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2 < 67f8f2bae8e7ac72e09def2b667e44704c4d1ee1, >= 3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2 < a97f221651fcdc891166e9bc270e3d9bfa5a0080, >= 3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2 < e3f647e4b642f9f6d32795a16f92c116c138d2af, >= 3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2 < 065d5f17096ec9161180e2c890afdff4dc6125f2, >= 3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2 < d68c17402442f5f494a2c3ebde5cb82f6aa9160a, >= 3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2 < 65583f9e070db7bece20710cfa2e3daeb0b831d9, >= 3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2 < 29b22badb7a84b783e3a4fffca16f7768fb31205, >= 4.10, >= 4.10 < 5.4.257, >= 5.5 < 5.10.195, >= 5.11 < 5.15.132, >= 5.16 < 6.1.53, >= 6.2 < 6.4.16, >= 6.5 < 6.5.3
Fixed versions
5.4.257, 5.10.195, 5.15.132, 6.1.53, 6.4.16, 6.5.3

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that Linux Linux, linux kernel and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE
CWE-416