CVE-2026-98547 Linux CVE debrief

Who should care

Linux kernel developers and administrators who use the `af_packet` feature and need to ensure the security and stability of their systems. They should review and apply the provided patch to fix the integer overflow vulnerability and implement compensating controls to prevent denial-of-service (DoS) attacks. Additionally, they should monitor system logs for potential security incidents and perform regular security audits to identify potential

Why it matters

The vulnerability allows for a denial-of-service (DoS) attack when a specific set of conditions are met, involving the `af_packet` and `TPACKET_V3` features.

• Denial-of-service (DoS) attacks may occur when a specific set of conditions are met
• System may become unresponsive due to the immediate timer expiration

Technical summary

The vulnerability is caused by an integer overflow in the `prb_calc_retire_blk_tmo()` function, which can lead to a negative relative timeout and an immediate timer expiration. The function computes in 32-bit int arithmetic, which can cause an overflow when the block size is large. The vulnerability can be triggered by setting the `tp_block_size` to a large value, such as 256MiB, and the `div` value to 1. This can cause the system to become unresponsive due to the immediate timer expiration. The vulnerability affects Linux kernel developers and administrators who need to review and apply the provided patch to fix the integer overflow vulnerability.

Defensive priority

High

Recommended defensive actions

• Review and apply the provided patch to fix the integer overflow vulnerability
• Restrict access to the `af_packet` feature to only necessary users
• Monitor system logs for potential denial-of-service (DoS) attacks
• Perform a thorough review of the system configuration and network exposure
• Implement compensating controls, such as rate limiting or traffic shaping
• Track exceptions and retest remediated assets to ensure the vulnerability is fully resolved
• Consider implementing additional security measures, such as network segmentation or access controls

Evidence notes

The vulnerability is caused by an integer overflow in the `prb_calc_retire_blk_tmo()` function, which can lead to a negative relative timeout and an immediate timer expiration. The function computes in 32-bit int arithmetic, which can cause an overflow when the block size is large. The vulnerability can be triggered by setting the `tp_block_size` to a large value, such as 256MiB, and the `div` value to 1. The vulnerability affects Linux kernel developers and administrators who need to review and apply the provided patch to fix the

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.