High [CVE-2026-53228] reload inner IPv6 header after GSO offloads
This high-severity Red Hat Linux advisory covers CVE-2026-53228 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 6.
Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.
VulniPulse record published Record updated
Summary
In the Linux kernel, the following vulnerability has been resolved: ipv6: sit: reload inner IPv6 header after GSO offloads ipip6_tunnel_xmit() caches the inner IPv6 header pointer at function entry and continues using it after iptunnel_handle_offloads(). For GSO skbs, iptunnel_handle_offloads() calls skb_header_unclone().
When the skb header is cloned, skb_header_unclone() can call pskb_expand_head(), which may move the skb head. The pskb_expand_head() contract requires pointers into the skb header to be reloaded after the call.
If the later skb_realloc_headroom() branch is not taken, SIT uses the stale iph6 pointer to read the inner hop limit and DS field. That can read from a freed skb head after the old head's remaining clone is released.
Reload iph6 after the offload helper succeeds and before subsequent reads from the inner IPv6 header. Keep the existing reload after skb_realloc_headroom(), since that branch can also replace the skb.
A flaw was found in the Linux kernel's Simple Internet Transition (SIT) tunnel driver for IPv6. When processing network traffic with Generic Segmentation Offload (GSO) enabled, the driver may use a stale pointer to the inner IPv6 header after the socket buffer (skb) head has been reallocated.
This can lead to reading from freed memory, potentially allowing an attacker to cause a denial of service or gain access to sensitive information.
Is CVE-2026-53228 exploited?
No exploitation is reported in the sources VulniPulse tracks: CVE-2026-53228 is not in the CISA KEV catalog (checked ) and this advisory does not report exploitation. That is not proof the vulnerability cannot be exploited.
How do I fix CVE-2026-53228?
Upgrade to a fixed release named by Red Hat:
- kernel-0:6.12.0-211.52.1.el10_2
- kernel-rt-0:4.18.0-553.164.1.rt7.505.el8_10
- kernel-0:4.18.0-553.164.1.el8_10
- RHSA-2026:64775
- RHSA-2026:68532
- RHSA-2026:68531
Confirm against the vendor advisory before you patch.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative. Check it before change work.
Official advisory · high-confidence parse· fetched 15 days ago·verify at source
- kernel-0:6.12.0-211.52.1.el10_2
- kernel-rt-0:4.18.0-553.164.1.rt7.505.el8_10
- kernel-0:4.18.0-553.164.1.el8_10
- RHSA-2026:64775
- RHSA-2026:68532
- RHSA-2026:68531
Official advisory · high-confidence parse· fetched 15 days ago·verify at source
Mitigation
Upgrade to a fixed release: kernel-0:6.12.0-211.52.1.el10_2, kernel-rt-0:4.18.0-553.164.1.rt7.505.el8_10, kernel-0:4.18.0-553.164.1.el8_10, RHSA-2026:64775, RHSA-2026:68532, RHSA-2026:68531. That is the remediation for this advisory.
The vendor advisory may list interim mitigations or workarounds not captured here. Review it before change work.
Official advisory · high-confidence parse· fetched 15 days ago·verify at source
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