CVE-2023-3776 Use-after-free in Linux kernel's net/sched: cls_fw component

What is CVE-2023-3776?

CVE-2023-3776 is a high-severity use after free vulnerability in Debian Debian Linux, published on 21 Jul 2023. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

A use-after-free vulnerability in the Linux kernel's net/sched: cls_fw component can be exploited to achieve local privilege escalation.

If tcf_change_indev() fails, fw_set_parms() will immediately return an error after incrementing or decrementing the reference counter in tcf_bind_filter(). If an attacker can control the reference counter and set it to zero, they can cause the reference to be freed, leading to a use-after-free vulnerability.

We recommend upgrading past commit 0323bce598eea038714f941ce2b22541c46d488f.

Weakness: CWE-416

Which versions are affected by CVE-2023-3776?

It affects 2 products.

Products include Debian Debian Linux, Linux kernel.

How do I fix CVE-2023-3776?

Apply the vendor's patch.

Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.

Is CVE-2023-3776 being exploited?

There is no known exploitation of CVE-2023-3776 in the wild and no public exploit code.

Public exploit code: 1 proofs of concept on GitHub.

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All Debian Debian Linux vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as AZL-27677, DEBIAN-CVE-2023-3776, GHSA-fcg7-9x44-gx43, UBUNTU-CVE-2023-3776.