Integer overflow in Linux kernel - CVE-2026-63889

Vulnerability identifier: #VU138756

CSH Severity: Medium

CVSS v4: 7.1 [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]

CVE-ID: CVE-2026-63889

CWE-ID: CWE-190

Exploitation vector: Adjecent network

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to an infinite loop caused by an integer truncation error in the FPIN pname walker in scsi_transport_fc when processing a crafted FPIN ELS frame. A remote attacker can send a crafted Fibre Channel fabric frame to cause a denial of service.

Exploitation requires the ability to inject Fibre Channel fabric traffic to an lpfc or qla2xxx Linux initiator, such as from a compromised switch or fabric controller, or from a same-zone N_Port on a fabric that permits source spoofing.

Linux kernel
openEuler
Ubuntu
kernel-debuginfo
python3-perf-debuginfo
python3-perf
perf-debuginfo
perf
kernel-tools-devel
kernel-tools-debuginfo
kernel-tools
kernel-source
kernel-headers
kernel-extra-modules
kernel-devel
kernel-debugsource
bpftool-debuginfo
bpftool
kernel
linux-ibm (Ubuntu package)
linux-aws (Ubuntu package)
linux-azure (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-nvidia-bos (Ubuntu package)

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
kernel-debuginfo - update to 6.6.0-145.3.29.160
python3-perf-debuginfo - update to 6.6.0-145.3.29.160
python3-perf - update to 6.6.0-145.3.29.160
perf-debuginfo - update to 6.6.0-145.3.29.160
perf - update to 6.6.0-145.3.29.160
kernel-tools-devel - update to 6.6.0-145.3.29.160
kernel-tools-debuginfo - update to 6.6.0-145.3.29.160
kernel-tools - update to 6.6.0-145.3.29.160
kernel-source - update to 6.6.0-145.3.29.160
kernel-headers - update to 6.6.0-145.3.29.160
kernel-extra-modules - update to 6.6.0-145.3.29.160
kernel-devel - update to 6.6.0-145.3.29.160
kernel-debugsource - update to 6.6.0-145.3.29.160
bpftool-debuginfo - update to 6.6.0-145.3.29.160
bpftool - update to 6.6.0-145.3.29.160
kernel - update to 6.6.0-145.3.29.160
linux-ibm (Ubuntu package) - addressed in versions 7.0.0-1008.8, 7.0.0-1010.10
linux-aws (Ubuntu package) - addressed in versions 7.0.0-1009.9, 7.0.0-1015.15
linux-azure (Ubuntu package) - addressed in versions 7.0.0-1009.9, 7.0.0-1010.10
linux-nvidia (Ubuntu package) - addressed in versions 7.0.0-1016.16, 7.0.0-1016.16~24.04.1
linux-nvidia-bos (Ubuntu package) - update to 7.0.0-2016.16

• https://git.kernel.org/stable/c/07776b7779c9426982c1ad74aad91bd531593790
• https://git.kernel.org/stable/c/163bd704d7515c3df6c2e03bcba93d1db79edbff
• https://git.kernel.org/stable/c/29f126f09e34a425b376b3646c89aa7cc18b142c
• https://git.kernel.org/stable/c/35461d23744175a78b6280293892cca357c22793
• https://git.kernel.org/stable/c/a9a39233ec1fc9f97ea1340a4d09bb7ec2be5153
• https://git.kernel.org/stable/c/bdff76dff6ec23d6fe35812fa33e5c4ce2cdb770
• https://git.kernel.org/stable/c/ee57b89e5da9fffbe0d26647e4ff0750dacb9943

• Integer overflow in Linux kernel scsi driver
• Ubuntu update for linux-ibm
• Ubuntu update for linux-azure
• Ubuntu update for linux-aws
• Ubuntu update for linux-nvidia-bos
• Ubuntu update for linux-nvidia
• openEuler 24.03 LTS SP3 update for kernel