Bug 2467122 (CVE-2026-43171)

Summary: CVE-2026-43171 kernel: EFI/CPER: don't dump the entire memory region
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
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 EFI/CPER component. This vulnerability occurs because the `cper_print_fw_err()` function does not adequately validate the length of error records against a provided offset. A malicious or malformed firmware could exploit this by providing an offset that causes an integer underflow, leading to the dumping of large memory regions. This can result in sensitive data disclosure or a system crash (Denial of Service).
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Description OSIDB Bzimport 2026-05-06 13:05:29 UTC 
In the Linux kernel, the following vulnerability has been resolved:

EFI/CPER: don't dump the entire memory region

The current logic at cper_print_fw_err() doesn't check if the
error record length is big enough to handle offset. On a bad firmware,
if the ofset is above the actual record, length -= offset will
underflow, making it dump the entire memory.

The end result can be:

 - the logic taking a lot of time dumping large regions of memory;
 - data disclosure due to the memory dumps;
 - an OOPS, if it tries to dump an unmapped memory region.

Fix it by checking if the section length is too small before doing
a hex dump.

[ rjw: Subject tweaks ]
Comment 1 Keith Grant 2026-05-06 19:55:05 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026050635-CVE-2026-43171-8549@gregkh/T