Improper input validation in Linux kernel - CVE-2026-63890
Published: July 20, 2026
Vulnerability identifier: #VU138757
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-63890
CWE-ID: CWE-20
Exploitation vector: Adjecent network
Exploit availability:
No public exploit available
Vendor: Linux Foundation
Affected software:
Linux kernel
Linux kernel
Detailed vulnerability description
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to improper input validation in fcoe_ctlr_recv_clr_vlink() in drivers/scsi/fcoe/fcoe_ctlr.c when processing FIP CVL frames. A remote attacker can send a crafted FIP CVL frame with a zero-length non-critical descriptor to cause a denial of service.
Exploitation is limited to an unauthenticated layer 2 peer on the FCoE control VLAN and can block subsequent FIP frames on the affected controller.
How to mitigate CVE-2026-63890
Install security update from vendor's repository.
Sources
- https://git.kernel.org/stable/c/0e3c6e5a8fc15a74dfb1e0c1df9f1da73600a81a
- https://git.kernel.org/stable/c/14dd80a20a72ce334adcc2d67402360527065948
- https://git.kernel.org/stable/c/549859a1131052b07dff11a448e9f3221a40f260
- https://git.kernel.org/stable/c/80a0cd307205236ca28aa49bc553f58edcb9bf3a
- https://git.kernel.org/stable/c/9eed1bd59937e6828b00d2f2dfef631d964f3636
- https://git.kernel.org/stable/c/d179949d2175d2857d1c3a275a22bea58bcc5d36
- https://git.kernel.org/stable/c/d537d29d51c8b808469e5adacf3e5a0092700738
- https://git.kernel.org/stable/c/fda976f7390bb5d1e9b84ef11ebb17323038e0c6