Unchecked Return Value in Linux kernel - CVE-2026-98879

Vulnerability identifier: #VU157629

CSH Severity: Low

CVSS v4: 6.7 [CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-98879

CWE-ID: CWE-252

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local privileged user to cause a denial of service by triggering a kernel assertion failure.

The vulnerability exists due to an unchecked return value from sb_set_blocksize() in isofs_fill_super() when mounting an ISO filesystem with a block size greater than PAGE_SIZE. A local privileged user can cause such a filesystem to be mounted to trigger the BUG_ON(offset >= folio_size(folio)) assertion in folio_set_bh() during the first __bread_gfp() call, causing a denial of service.

Linux kernel
Ubuntu
linux-nvidia-tegra (Ubuntu package)
linux-nvidia-tegra-igx (Ubuntu package)
linux-nvidia-tegra-5.15 (Ubuntu package)
linux (Ubuntu package)
linux-gcp (Ubuntu package)
linux-oracle (Ubuntu package)
linux-aws (Ubuntu package)
linux-ibm (Ubuntu package)
linux-hwe-7.0 (Ubuntu package)
linux-oem-7.0 (Ubuntu package)

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
linux-nvidia-tegra (Ubuntu package) - update to 5.15.0-1070.72
linux-nvidia-tegra-igx (Ubuntu package) - update to 5.15.0-1059.59
linux-nvidia-tegra-5.15 (Ubuntu package) - update to 5.15.0-1070.72~20.04.1
linux (Ubuntu package) - update to 7.0.0-42.42
linux-gcp (Ubuntu package) - update to 7.0.0-1016.18
linux-oracle (Ubuntu package) - update to 7.0.0-1015.16
linux-aws (Ubuntu package) - update to 7.0.0-1016.17
linux-ibm (Ubuntu package) - update to 7.0.0-1017.17
linux-hwe-7.0 (Ubuntu package) - update to 7.0.0-42.42~24.04.1
linux-oem-7.0 (Ubuntu package) - update to 7.0.0-1017.17

• https://git.kernel.org/stable/c/25ef4c4d9f0e96fb89c0ae0d7127c3f12a31bc32
• https://git.kernel.org/stable/c/28d1f6aa14f5924e36602b7a31c9141d34de0b9c
• https://git.kernel.org/stable/c/61f277bf35f533b602984f0e55900111fe52f31a
• https://git.kernel.org/stable/c/6db7f0ba365786304558db6a3d52013ae176e03e
• https://git.kernel.org/stable/c/9584ab6283721e5aab485c79bd06c2f78d89e55c
• https://git.kernel.org/stable/c/9c97e3b1152d3092581745189f5d2f04c6404ef9
• https://git.kernel.org/stable/c/cebde6d88e34396c29f2f001d90e921677cc17d6

• Unchecked Return Value in Linux kernel isofs
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux, linux-aws, linux-gcp and more
• Ubuntu update for linux-nvidia-tegra, linux-nvidia-tegra-5.15, linux-nvidia-tegra-igx
• Ubuntu update for linux, linux-aws, linux-aws-5.15 and more