Critical 9.8Published Jun 25, 2026

CVE-2026-53228ipv6: sit: reload inner IPv6 header after GSO offloads

Updated under an hour ago (Oct 27, 2026, 2:40 AM ET)

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No exploitation reported and no EPSS estimate yet.

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Exploited in the last 30 days

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.

CVSS: 9.8 CRITICAL (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): CWE-416
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Modified
Record last updated: Oct 19, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from 14909664e4e192f4c6f6fcdccd9919af7cf783ab before fddd41445a0537b093e6b3f6232c9933cad1e48b; 14909664e4e192f4c6f6fcdccd9919af7cf783ab builds before 1132e5edc2866c3530be17622153a597095f0e43; 14909664e4e192f4c6f6fcdccd9919af7cf783ab builds before 9c67b44edb3598d234efae6e44649eb993c03da5; 14909664e4e192f4c6f6fcdccd9919af7cf783ab builds before 0bfa7bba1f41aaf5f0604dc712bb4701493e3aa0; 14909664e4e192f4c6f6fcdccd9919af7cf783ab builds before 59f80c919713250fe5d25a4d9aea4e49580fa1d4; 14909664e4e192f4c6f6fcdccd9919af7cf783ab builds before 2fa49b2715e1bad12ce3b0fa64e234d9582c8193; from 14909664e4e192f4c6f6fcdccd9919af7cf783ab before cb658c2f5f7977c2a1c77c9f239f4bc8196edb5c; from 14909664e4e192f4c6f6fcdccd9919af7cf783ab before f0e42f0c4337b1f220de1ddd63f47197c7dee4de	CNA record
Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem siemens:simatic_s7_1500_tm_mfp_gnu_linux_subsystem (from the name)	all versions	CISA ADP
linux linux_kernel linux:linux_kernel	from 3.18 before 5.10.259; from 5.11 before 5.15.210; from 5.16 before 6.1.176; from 6.2 before 6.6.143; from 6.7 before 6.12.94; from 6.13 before 6.18.36; from 6.19 before 7.0.13; 7.1; and 6 more ranges	NVD

References

References

https://git.kernel.org/stable/c/fddd41445a0537b093e6b3f6232c9933cad1e48b	patch
https://git.kernel.org/stable/c/1132e5edc2866c3530be17622153a597095f0e43	patch
https://git.kernel.org/stable/c/9c67b44edb3598d234efae6e44649eb993c03da5	patch
https://git.kernel.org/stable/c/0bfa7bba1f41aaf5f0604dc712bb4701493e3aa0	patch
https://git.kernel.org/stable/c/59f80c919713250fe5d25a4d9aea4e49580fa1d4	patch
https://git.kernel.org/stable/c/2fa49b2715e1bad12ce3b0fa64e234d9582c8193	patch
https://git.kernel.org/stable/c/cb658c2f5f7977c2a1c77c9f239f4bc8196edb5c	patch
https://git.kernel.org/stable/c/f0e42f0c4337b1f220de1ddd63f47197c7dee4de	patch
https://cert-portal.siemens.com/productcert/html/ssa-784472.html

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.