Bug 2506826 (CVE-2026-64245)

Summary: CVE-2026-64245 kernel: fbdev: modedb: fix a possible UAF in fb_find_mode()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Priority: medium    
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's framebuffer device (fbdev) subsystem. Specifically, within the fb_find_mode() function, a use-after-free (UAF) vulnerability exists. This occurs because a memory buffer is released while still being referenced, potentially allowing an attacker to access or manipulate freed memory. Such an exploit could lead to system instability, denial of service, or potentially arbitrary code execution.
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Description OSIDB Bzimport 2026-07-24 16:06:41 UTC
In the Linux kernel, the following vulnerability has been resolved:

fbdev: modedb: fix a possible UAF in fb_find_mode()

If mode_option is NULL, it is assigned from mode_option_buf:

  if (!mode_option) {
    fb_get_options(NULL, &mode_option_buf);
    mode_option = mode_option_buf;
  }

Later, name is assigned from mode_option:

  const char *name = mode_option;

However, mode_option_buf is freed before name is no longer used:

  kfree(mode_option_buf);

while name is still accessed by:

  if ((name_matches(db[i], name, namelen) ||

Since name aliases mode_option_buf, this may result in a
use-after-free.

Fix this by extending the lifetime of mode_option_buf until the end of the
function by using scope-based resource management for cleanup.

Comment 1 Mauro Matteo Cascella 2026-07-28 12:36:28 UTC
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026072418-CVE-2026-64245-d57c@gregkh/T