Medium [CVE-2026-80993] Linux kernel: Denial of Service due to incorrect PCS validation in phylink
This medium-severity Red Hat Linux advisory covers CVE-2026-80993.
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Summary
A flaw was found in the Linux kernel's `net: phylink` component. The `phylink_inband_caps()` function does not correctly validate the return value from `mac_select_pcs`, which can return an error pointer instead of a valid Physical Coding Sublayer (PCS) object.
This oversight can lead to dereferencing an invalid pointer, causing a kernel panic. A kernel panic results in a system crash, leading to a Denial of Service (DoS).
Red Hat severity: Important — CVSS 4.1 (CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H). Weakness: CWE-476.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · medium-confidence parse· fetched 37 minutes ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · medium-confidence parse· fetched 37 minutes ago·verify at source
Mitigation
The source record does not include mitigation steps. That is not a statement that no fix exists — read the vendor advisory below for the authoritative guidance.
Official advisory · medium-confidence parse· fetched 37 minutes ago·verify at source
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