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High severity7.8NVD Advisory· Published Dec 18, 2023· Updated May 12, 2026

CVE-2023-6817

CVE-2023-6817

Description

A use-after-free vulnerability in the Linux kernel's netfilter: nf_tables component can be exploited to achieve local privilege escalation.

The function nft_pipapo_walk did not skip inactive elements during set walk which could lead double deactivations of PIPAPO (Pile Packet Policies) elements, leading to use-after-free.

We recommend upgrading past commit 317eb9685095678f2c9f5a8189de698c5354316a.

AI Insight

LLM-synthesized narrative grounded in this CVE's description and references.

Use-after-free in Linux kernel nf_tables pipapo set walk allows local privilege escalation with CAP_NET_ADMIN; fixed in 6.7-rc5.

Vulnerability

Details

The vulnerability resides in the nft_pipapo_walk function within the Linux kernel's netfilter nf_tables subsystem. During a set walk, the function fails to skip inactive elements, which can lead to double deactivations of PIPAPO (Pile Packet Policies) elements. This improper handling results in a use-after-free condition [3].

Exploitation

Exploitation requires the CAP_NET_ADMIN capability, allowing a local attacker to issue the NFT_MSG_DELSETELEM command without specifying a set element. This triggers nft_set_flush(), which calls the vulnerable walk function. The walk processes inactive elements again, causing a use-after-free that can be leveraged for privilege escalation or denial of service [3].

Impact

A successful exploit can lead to local privilege escalation or system denial of service. The vulnerability is rated High with a CVSS v3 base score of 7.8. It also affects Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem, as listed in Siemens advisory SSA-265688 [2].

Mitigation

The issue is fixed in Linux kernel version 6.7-rc5 with commit 317eb9685095678f2c9f5a8189de698c5354316a. Backports have been applied to stable kernels 5.10.204, 5.15.143, 6.1.68, and 6.6.7 [4]. Users are advised to update their kernels to the latest patched versions.

References
  1. SSA-265688
  2. security - CVE-2023-6817: Linux kernel: use-after-free in nf_tables
  3. security - Re: CVE-2023-6817: Linux kernel: use-after-free in nf_tables

AI Insight generated on May 20, 2026. Synthesized from this CVE's description and the cited reference URLs; citations are validated against the source bundle.

Affected products

168

Patches

0

No patches discovered yet.

Vulnerability mechanics

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References

8

News mentions

0

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