CVE-2026-53003

A flaw was found in the Linux kernel's Point-to-Point Protocol over Ethernet (PPPoE) driver. A remote attacker or a peer with a misconfigured implementation could send specially crafted Protocol Field Compression (PFC) frames. This could lead to a one-byte shift in the PPP payload, causing a four-byte misalignment of the network header. On certain architectures, this misalignment may trigger unaligned access exceptions, potentially leading to a denial of service or system instability.

This vulnerability is evaluated as having Moderate impact because exploitation is constrained to a denial of service and requires an active PPPoE interface communicating with an untrusted or misconfigured peer. PPPoE is not configured or enabled by default on standard Red Hat Enterprise Linux deployments, substantially limiting exposure in typical production environments. Furthermore, unaligned access exceptions primarily disrupt specific hardware architectures that enforce strict memory boundary alignment, without allowing unauthorized data disclosure or privilege escalation.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.