Linux Kernel up to 6.11.6 bpf_iter_bits_new nr_words stack-based overflow

Summaryinfo

A vulnerability classified as critical has been found in Linux Kernel up to 6.11.6. This affects the function bpf_iter_bits_new. This manipulation of the argument nr_words causes stack-based overflow. This vulnerability is handled as CVE-2024-50253. There is not any exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical was found in Linux Kernel up to 6.11.6. Affected by this vulnerability is the function bpf_iter_bits_new. The manipulation of the argument nr_words with an unknown input leads to a stack-based overflow vulnerability. The CWE definition for the vulnerability is CWE-121. A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function). As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: bpf: Check the validity of nr_words in bpf_iter_bits_new() Check the validity of nr_words in bpf_iter_bits_new(). Without this check, when multiplication overflow occurs for nr_bits (e.g., when nr_words = 0x0400-0001, nr_bits becomes 64), stack corruption may occur due to bpf_probe_read_kernel_common(..., nr_bytes = 0x2000-0008). Fix it by limiting the maximum value of nr_words to 511. The value is derived from the current implementation of BPF memory allocator. To ensure compatibility if the BPF memory allocator's size limitation changes in the future, use the helper bpf_mem_alloc_check_size() to check whether nr_bytes is too larger. And return -E2BIG instead of -ENOMEM for oversized nr_bytes.

The advisory is shared at git.kernel.org. This vulnerability is known as CVE-2024-50253 since 10/21/2024. The exploitation appears to be easy. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 10/02/2025).

The vulnerability scanner Nessus provides a plugin with the ID 216493 (Ubuntu 24.10 : Linux kernel vulnerabilities (USN-7276-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.11.7 eliminates this vulnerability. Applying the patch c9539e09c678/393397fbdcad is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (216493) and CERT Bund (WID-SEC-2024-3397). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Affected

• Debian Linux
• Amazon Linux 2
• Red Hat Enterprise Linux
• Ubuntu Linux
• SUSE Linux
• Oracle Linux
• Open Source eCryptfs
• Siemens SIMATIC S7
• SUSE openSUSE
• RESF Rocky Linux
• Dell NetWorker
• Dell Avamar
• IBM QRadar SIEM

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.11.0
• 6.11.1
• 6.11.2
• 6.11.3
• 6.11.4
• 6.11.5
• 6.11.6

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

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Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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