Integer underflow in Linux kernel - CVE-2026-74349

Vulnerability identifier: #VU142837

CSH Severity: Low

CVSS v4: 6.9 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-74349

CWE-ID: CWE-191

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to cause unintended block trimming beyond the requested range.

The vulnerability exists due to an integer underflow in ocfs2_trim_mainbm() when processing a FITRIM range shorter than a cluster. A local user can submit a specially crafted FITRIM range to cause unintended block trimming beyond the requested range.

The issue occurs on filesystems where the cluster size is larger than the block size.

Linux kernel
Ubuntu
linux-nvidia (Ubuntu package)
linux-nvidia-tegra (Ubuntu package)
linux-gcp-7.0 (Ubuntu package)
linux (Ubuntu package)
linux-oem-7.0 (Ubuntu package)
linux-azure-7.0 (Ubuntu package)
linux-azure (Ubuntu package)

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
linux-nvidia (Ubuntu package) - addressed in versions 5.15.0-1112.113, 5.15.0.1112.112
linux-nvidia-tegra (Ubuntu package) - update to 6.8.0-1036.39+1
linux-gcp-7.0 (Ubuntu package) - addressed in versions 7.0.0-38.38~24.04.4, 7.0.0-1013.13~24.04.1, 7.0.0-1014.14~24.04.1
linux (Ubuntu package) - addressed in versions 7.0.0-38.38, 7.0.0-38.38.1, 7.0.0-1008.9, 7.0.0-1013.13~24.04.1, 7.0.0-1014.14, 7.0.0-1015.15
linux-oem-7.0 (Ubuntu package) - update to 7.0.0-1015.15
linux-azure-7.0 (Ubuntu package) - addressed in versions 7.0.0-1016.16~24.04.1, 7.0.0-1017.17~24.04.1
linux-azure (Ubuntu package) - addressed in versions 7.0.0-1016.16, 7.0.0-1017.17

• https://git.kernel.org/stable/c/06c0a0431b9856506fcd9b2c1b0c6136567d756d
• https://git.kernel.org/stable/c/2c13e02592b918be7725ab5965e01ef4e46c4b57
• https://git.kernel.org/stable/c/346314bb0cc2fc52b50b73d6ecc62e0217455c2e
• https://git.kernel.org/stable/c/3fa7139b5f42731a61f78c42433adae13f9adc21
• https://git.kernel.org/stable/c/441abb77222f155e8d931dbabb465466db01cfd7
• https://git.kernel.org/stable/c/ca1afd88f5eaaff9168e1466e5401385edf59543
• https://git.kernel.org/stable/c/d903d59c0315f59bdf0214b4f13d71c9feb2c45c
• https://git.kernel.org/stable/c/e652d0f5108e447b22da4249bcd23dd1b63c73dd

• Integer underflow in Linux kernel ocfs2
• Ubuntu update for linux-gcp-7.0
• Ubuntu update for linux-nvidia
• Ubuntu update for linux-azure-7.0
• Ubuntu update for linux-nvidia-tegra
• Ubuntu update for linux
• Ubuntu update for linux-azure
• Ubuntu update for linux-oem-7.0