Bug 2502369 (CVE-2026-63993) - CVE-2026-63993 kernel: vxlan: do not reuse cached ip_hdr() value after skb_tunnel_check_pmtu()
Summary: CVE-2026-63993 kernel: vxlan: do not reuse cached ip_hdr() value after skb_tu...
Keywords:
Status: NEW
Alias: CVE-2026-63993
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-07-19 16:04 UTC by OSIDB Bzimport
Modified: 2026-10-30 13:05 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2026:64775 0 None None None 2026-09-08 07:19:54 UTC
Red Hat Product Errata RHSA-2026:76739 0 None None None 2026-10-08 09:50:11 UTC
Red Hat Product Errata RHSA-2026:83707 0 None None None 2026-10-16 13:30:17 UTC
Red Hat Product Errata RHSA-2026:91489 0 None None None 2026-10-28 01:10:01 UTC
Red Hat Product Errata RHSA-2026:91492 0 None None None 2026-10-28 01:14:29 UTC
Red Hat Product Errata RHSA-2026:92993 0 None None None 2026-10-30 06:30:50 UTC
Red Hat Product Errata RHSA-2026:93047 0 None None None 2026-10-30 13:05:48 UTC

Description OSIDB Bzimport 2026-07-19 16:04:23 UTC 
In the Linux kernel, the following vulnerability has been resolved:

vxlan: do not reuse cached ip_hdr() value after skb_tunnel_check_pmtu()

skb_tunnel_check_pmtu() can change skb->head.

Reusing old_iph afer skb_tunnel_check_pmtu() can cause an UAF.

Use instead ip_hdr(skb) as done in drivers/net/bareudp.c
and drivers/net/geneve.c.

Found by Sashiko.
Comment 1 Keith Grant 2026-07-21 23:48:28 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026071905-CVE-2026-63993-165e@gregkh/T
Comment 4 errata-xmlrpc 2026-09-08 07:19:53 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2026:64775 https://access.redhat.com/errata/RHSA-2026:64775
Comment 6 Jon Orris 2026-10-08 09:50:10 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2026:76739 https://access.redhat.com/errata/RHSA-2026:76739
Comment 7 Jon Orris 2026-10-16 13:30:17 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10.0 Extended Update Support

Via RHSA-2026:83707 https://access.redhat.com/errata/RHSA-2026:83707
Comment 10 Jon Orris 2026-10-28 01:10:00 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions

Via RHSA-2026:91489 https://access.redhat.com/errata/RHSA-2026:91489
Comment 11 Jon Orris 2026-10-28 01:14:28 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.6 Extended Update Support

Via RHSA-2026:91492 https://access.redhat.com/errata/RHSA-2026:91492
Comment 12 Jon Orris 2026-10-30 06:30:49 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions

Via RHSA-2026:92993 https://access.redhat.com/errata/RHSA-2026:92993
Comment 13 Jon Orris 2026-10-30 13:05:47 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions

Via RHSA-2026:93047 https://access.redhat.com/errata/RHSA-2026:93047
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