SEPTEMBER 8, 2026
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Case File

CVE-2026-63993

CRITICAL · CVSS 9.8 EPSS 0.51%

Source: NVD + CISA KEV + EPSS · Published 2026-07-19 · Last synced 2026-08-18

CyberRota Analysis

AI-Generated

A vulnerability in the Linux kernel affects the vxlan implementation, where reusing a cached IP header after the skb_tunnel_check_pmtu() function can lead to a use-after-free (UAF) condition. This critical flaw, with a CVSS score of 9.8, could allow attackers to execute arbitrary code or crash the system, posing significant risks to system integrity and availability. Organizations using Linux-based systems, particularly those leveraging vxlan for network virtualization, should prioritize patching this vulnerability to mitigate potential exploitation.

CVE
CVE-2026-63993
Severity
CRITICAL
CVSS
9.8
EPSS
0.51%
Linux

Original NVD 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.