Medium [CVE-2026-89555] Linux kernel: MPLS use-after-free vulnerability causes denial of service.
This medium-severity Red Hat Linux advisory covers CVE-2026-89555 affecting Red Hat OpenShift Container Platform 4.
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Summary
A flaw was found in the Linux kernel's Multiprotocol Label Switching (MPLS) subsystem. When processing specially crafted Geneve packets through an MPLS multipath setup, a use-after-free vulnerability occurs.
This issue arises because a cached header pointer (`hdr`) is not reloaded after `pskb_may_pull()` potentially reallocates the packet buffer, leading to `hdr` pointing to freed memory. A remote attacker could exploit this to trigger a kernel crash, resulting in a denial of service.
Red Hat severity: Moderate — CVSS 5.9 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H). Weakness: CWE-825.
Affected Red Hat products: Red Hat OpenShift Container Platform 4. Red Hat does not currently list a fixing RHSA for this CVE.
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 2 hours 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 2 hours 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 2 hours ago·verify at source
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