CVE-2025-40337: In the Linux kernel, the following vulnerability has been resolved: net: stmmac: Correctly handle Rx checksum offload errors The stmmac_rx function ...

Description

In the Linux kernel, the following vulnerability has been resolved: net: stmmac: Correctly handle Rx checksum offload errors The stmmac_rx function would previously set skb->ip_summed to CHECKSUM_UNNECESSARY if hardware checksum offload (CoE) was enabled and the packet was of a known IP ethertype. However, this logic failed to check if the hardware had actually reported a checksum error. The hardware status, indicating a header or payload checksum failure, was being ignored at this stage. This could cause corrupt packets to be passed up the network stack as valid. This patch corrects the logic by checking the `csum_none` status flag, which is set when the hardware reports a checksum error. If this flag is set, skb->ip_summed is now correctly set to CHECKSUM_NONE, ensuring the kernel's network stack will perform its own validation and properly handle the corrupt packet.

Metrics

EPSS Probability

0.19%

9.0th percentile

Probability of exploitation in the next 30 days. Learn more

References

Timeline

Published: Dec 9, 2025
Last Modified: Jun 17, 2026
Status: Deferred

Frequently Asked Questions

What is CVE-2025-40337?

In the Linux kernel, the following vulnerability has been resolved: net: stmmac: Correctly handle Rx checksum offload errors The stmmac_rx function would previously set skb->ip_summed to CHECKSUM_UNNECESSARY if hardware checksum offload (CoE) was enabled and the packet was of a known IP ethertype. However, this logic failed to check if the hardware had actually reported a checksum error. The hardware status, indicating a header or payload checksum failure, was being ignored at this stage. This could cause corrupt packets to be passed up the network stack as valid. This patch corrects the logic by checking the `csum_none` status flag, which is set when the hardware reports a checksum error. If this flag is set, skb->ip_summed is now correctly set to CHECKSUM_NONE, ensuring the kernel's network stack will perform its own validation and properly handle the corrupt packet.

How severe is CVE-2025-40337?

Severity scoring for CVE-2025-40337 is pending analysis. The EPSS model estimates a 0.19% probability of exploitation in the next 30 days.

How do I fix CVE-2025-40337?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.