Medium [CVE-2026-89563] Memory corruption in ip6_tunnel due to double-free vulnerability
This medium-severity Red Hat Linux advisory covers CVE-2026-89563.
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Summary
A flaw was found in the `ip6_tunnel` module of the Linux kernel. Incorrect handling of socket buffers (skb) during headroom reallocation in the `ip6_tnl_xmit()` function can lead to a double-free vulnerability.
This occurs when an error path is taken after the original skb has been consumed, but the caller still holds a pointer to it, potentially allowing the same memory to be freed twice. This memory corruption issue could lead to a denial of service or potentially arbitrary code execution.
Red Hat severity: Moderate — CVSS 4.4 (CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H). Weakness: CWE-1341.
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 24 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 24 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 24 minutes ago·verify at source
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