Bug 2507239 (CVE-2026-64297)

Summary: CVE-2026-64297 kernel: module: decompress: check return value of module_extend_max_pages()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: low    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel. An unchecked return value in the `module_extend_max_pages()` function within the module decompression logic can lead to a null pointer dereference. This vulnerability can be triggered if memory allocation fails during module loading, resulting in a kernel oops. This can allow a local attacker to cause a denial of service (DoS) by crashing the system.
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Description OSIDB Bzimport 2026-07-25 10:12:18 UTC 
In the Linux kernel, the following vulnerability has been resolved:

module: decompress: check return value of module_extend_max_pages()

module_extend_max_pages() calls kvrealloc() internally and returns
-ENOMEM on allocation failure. The return value is never checked.

If the initial allocation fails, info->pages remains NULL and
info->max_pages remains 0. Subsequent calls to module_get_next_page()
will attempt to dynamically grow the array by calling
module_extend_max_pages(info, 0) since info->used_pages is 0. This
results in kvrealloc(NULL, 0) returning ZERO_SIZE_PTR, which is treated
as a success, leading to a dereference of ZERO_SIZE_PTR and a kernel
oops.

Fix: add the missing error check after module_extend_max_pages() and
return immediately on failure. This matches the pattern used by every
other kvrealloc() caller in the module loading path.

[Sami: Corrected the analysis in the commit message.]
Comment 1 TEJ RATHI 2026-07-29 08:50:21 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026072506-CVE-2026-64297-5945@gregkh/T