Vulnerability details
CVE-2023-53338
lwt: Fix return values of BPF xmit ops
Official 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.
CVSS scores
| Score | Version | Source | Vector |
|---|---|---|---|
| 7.8High | 3.1 | CISA ADP / Vulnrichment (CISA-ADP) | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| 9.8Critical | 3.1 | CVEProject cvelistV5 (CNA) (Linux) | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
Affected products
| Vendor | Product | Versions | Source |
|---|---|---|---|
| Linux | Linux | 4.10 | CVEProject cvelistV5 (CNA) |
| Linux | Linux | 3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2 ≤ v < a97f221651fcdc891166e9bc270e3d9bfa5a0080 | CVEProject cvelistV5 (CNA) |
| Linux | Linux | 3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2 ≤ v < e3f647e4b642f9f6d32795a16f92c116c138d2af | CVEProject cvelistV5 (CNA) |
| Linux | Linux | 3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2 ≤ v < 065d5f17096ec9161180e2c890afdff4dc6125f2 | CVEProject cvelistV5 (CNA) |
| Linux | Linux | 3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2 ≤ v < 67f8f2bae8e7ac72e09def2b667e44704c4d1ee1 | CVEProject cvelistV5 (CNA) |
| Linux | Linux | 3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2 ≤ v < 65583f9e070db7bece20710cfa2e3daeb0b831d9 | CVEProject cvelistV5 (CNA) |
| Linux | Linux | 3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2 ≤ v < 29b22badb7a84b783e3a4fffca16f7768fb31205 | CVEProject cvelistV5 (CNA) |
| Linux | Linux | 3a0af8fd61f90920f6fa04e4f1e9a6a73c1b4fd2 ≤ v < d68c17402442f5f494a2c3ebde5cb82f6aa9160a | CVEProject cvelistV5 (CNA) |
References and advisories
7- https://git.kernel.org/stable/c/67f8f2bae8e7ac72e09def2b667e44704c4d1ee1
- https://git.kernel.org/stable/c/a97f221651fcdc891166e9bc270e3d9bfa5a0080
- https://git.kernel.org/stable/c/e3f647e4b642f9f6d32795a16f92c116c138d2af
- https://git.kernel.org/stable/c/065d5f17096ec9161180e2c890afdff4dc6125f2
- https://git.kernel.org/stable/c/d68c17402442f5f494a2c3ebde5cb82f6aa9160a
- https://git.kernel.org/stable/c/65583f9e070db7bece20710cfa2e3daeb0b831d9
- https://git.kernel.org/stable/c/29b22badb7a84b783e3a4fffca16f7768fb31205
Details
- Published
- 2025-09-17
- Last updated
- 2026-08-05
- State
- Published
- Assigner (CNA)
- Linux
Exploit prediction (EPSS)
SSVC assessment (CISA)
- Automatable
- No
- Exploitation
- None
- Technical impact
- Total
Weaknesses (CWE)
- CWE-416Use After Free