CVE-2026-89716: zram: validate deflate params
In the Linux kernel, the following vulnerability has been resolved:
zram: validate deflate params
We must validate user-supplied deflate winbits before we pass it to zlibdeflateworkspacesize(), which triggers BUGON() if winbits value is outside of valid ranges.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Configuration
In zram’s deflate path, validate user-supplied deflate winbits before passing it to zlib_deflate_workspacesize(); ensure BUG_ON is avoided by rejecting winbits values outside valid ranges.
Linux kernel (zram) validate deflate winbits before passing to zlib_deflate_workspacesize() = outside-of-valid-ranges -> reject/guard
Event History
Frequently Asked Questions
What condition is required to trigger the kernel failure?
An attacker or local user must be able to supply a deflate winbits value to zram that falls outside the valid range. The invalid value reaches zlib_deflate_workspacesize(), which triggers a BUG_ON().
What is the likely impact of successful exploitation?
The described behavior triggers a kernel BUG_ON(), which can cause a system crash or denial of service.
How can I determine whether a system is affected?
Review the Linux kernel version and applied stable patches against the referenced fixes. Systems that allow user-supplied zram deflate parameters and do not include the validation change may be affected.