CVE-2025-21676

CVE-2025-21676 is a medium-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-476.

Key facts

Description

In the Linux kernel, the following vulnerability has been resolved: net: fec: handle page_pool_dev_alloc_pages error The fec_enet_update_cbd function calls page_pool_dev_alloc_pages but did not handle the case when it returned NULL. There was a WARN_ON(!new_page) but it would still proceed to use the NULL pointer and then crash. This case does seem somewhat rare but when the system is under memory pressure it can happen. One case where I can duplicate this with some frequency is when writing over a smbd share to a SATA HDD attached to an imx6q. Setting /proc/sys/vm/min_free_kbytes to higher values also seems to solve the problem for my test case. But it still seems wrong that the fec driver ignores the memory allocation error and can crash. This commit handles the allocation error by dropping the current packet.

Frequently asked questions

What is CVE-2025-21676?
In the Linux kernel, the following vulnerability has been resolved: net: fec: handle page_pool_dev_alloc_pages error The fec_enet_update_cbd function calls page_pool_dev_alloc_pages but did not handle the case when it returned NULL. There was a WARN_ON(!new_page) but it would still proceed to use the NULL pointer and then crash. This case does seem somewhat rare but when the system is under memory pressure it can happen. One case where I can duplicate this with some frequency is when writing over a smbd share to a SATA HDD attached to an imx6q. Setting /proc/sys/vm/min_free_kbytes to higher values also seems to solve the problem for my test case. But it still seems wrong that the fec driver ignores the memory allocation error and can crash. This commit handles the allocation error by dropping the current packet.
How severe is CVE-2025-21676?
CVE-2025-21676 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2025-21676 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (10th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-21676?
CVE-2025-21676 primarily affects Linux Linux Kernel. In total, 8 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2025-21676?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-21676 have an EU (EUVD) identifier?
Yes. CVE-2025-21676 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-2625.
When was CVE-2025-21676 published?
CVE-2025-21676 was published on 2025-01-31 and last updated on 2026-06-17.

References

Affected products (8)

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