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.

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00176.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
Linux Linux unaffected
Version Status Constraints
4cb47a8644cc9eb8ec81190a50e79e6530d0297f affected < 6b8bfce9d2f774d2c2243e0248e03efb99bba6c0
4cb47a8644cc9eb8ec81190a50e79e6530d0297f affected < 9257f56ac47ef1976bcd056cf986a9988eeec67a
4cb47a8644cc9eb8ec81190a50e79e6530d0297f affected < 8d435d68d71fb875876b722f4136caf74f2f48bd
4cb47a8644cc9eb8ec81190a50e79e6530d0297f affected < dc3bfa050f873371e745bdf478b1f5b738e5733d
4cb47a8644cc9eb8ec81190a50e79e6530d0297f affected < 609e63312c29aad18026a1d3222e123d4b6b0feb
4cb47a8644cc9eb8ec81190a50e79e6530d0297f affected < 5303925e360527243b46a440a04667826bbc72b7
4cb47a8644cc9eb8ec81190a50e79e6530d0297f affected < a493efd4336cf19122ae0e4cbb3d31b32d70deea
4cb47a8644cc9eb8ec81190a50e79e6530d0297f affected < 7d9ef0cb271555d8cf39fefe6c981e1493b25ecf
Linux Linux affected
Version Status Constraints
5.9 affected —
0 unaffected < 5.9
5.10.259 unaffected ≤ 5.10.*
5.15.210 unaffected ≤ 5.15.*
6.1.176 unaffected ≤ 6.1.*
6.6.143 unaffected ≤ 6.6.*
6.12.93 unaffected ≤ 6.12.*
6.18.35 unaffected ≤ 6.18.*
7.0.12 unaffected ≤ 7.0.*
7.1 unaffected ≤ *

No data.

No data.

No data.

Project Subscriptions

Vendors Products
Linux Subscribe
Linux Kernel Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://git.kernel.org/stable/c/5303925e360527243b46a440a04667826bbc72b7 cve-icon
https://git.kernel.org/stable/c/609e63312c29aad18026a1d3222e123d4b6b0feb cve-icon
https://git.kernel.org/stable/c/6b8bfce9d2f774d2c2243e0248e03efb99bba6c0 cve-icon
https://git.kernel.org/stable/c/7d9ef0cb271555d8cf39fefe6c981e1493b25ecf cve-icon
https://git.kernel.org/stable/c/8d435d68d71fb875876b722f4136caf74f2f48bd cve-icon
https://git.kernel.org/stable/c/9257f56ac47ef1976bcd056cf986a9988eeec67a cve-icon
https://git.kernel.org/stable/c/a493efd4336cf19122ae0e4cbb3d31b32d70deea cve-icon
https://git.kernel.org/stable/c/dc3bfa050f873371e745bdf478b1f5b738e5733d cve-icon
History

Mon, 20 Jul 2026 14:45:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}

Sun, 19 Jul 2026 15:30:00 +0000

Type Values Removed Values Added
Description 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.
Title vxlan: do not reuse cached ip_hdr() value after skb_tunnel_check_pmtu()
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Projects

Sign in to view the affected projects.

cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-07-20T13:42:08.907Z

Reserved: 2026-07-19T07:54:57.025Z

Link: CVE-2026-63993

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses

No weakness.