Integer underflow in Linux kernel - CVE-2026-31649
Published: April 25, 2026
Vulnerability identifier: #VU127744
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-31649
CWE-ID: CWE-191
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vendor: Linux Foundation
Affected software:
Linux kernel
Linux kernel
Detailed vulnerability description
The vulnerability allows a local user to disclose sensitive information and cause memory corruption.
The vulnerability exists due to integer underflow in jumbo_frm() chain-mode implementation in the stmmac driver when processing a packet whose linear portion is smaller than the buffer size but whose total length exceeds it due to page fragments. A local user can send a specially crafted packet to disclose sensitive information and cause memory corruption.
On systems without an IOMMU, the issue can cause DMA mappings to reference kernel memory beyond the skb buffer.
How to mitigate CVE-2026-31649
Install security update from vendor's repository.
Sources
- https://git.kernel.org/stable/c/10d12b9240ebf96c785f0e2e4228318cd5f3a3eb
- https://git.kernel.org/stable/c/275bdf762e82082f064e60a92448fa2ac43cf95b
- https://git.kernel.org/stable/c/2c91b39912278d0878f9ba60ba04d2518b18a08d
- https://git.kernel.org/stable/c/513e06735f5be575b409d195822195348b164e48
- https://git.kernel.org/stable/c/51f4e090b9f87b40c21b6daadb5c06e6c0a07b67
- https://git.kernel.org/stable/c/6fca757c20396dc2e604dcc61922264e9e3dc803
- https://git.kernel.org/stable/c/a2b68a9a476b9544ff31f1fbcd5d80867a8a5e2f
- https://git.kernel.org/stable/c/b7b8012193fd98236d7ae05d4b553f010a77b2ef