CVE-2026-64316 in Linux
Summary
by MITRE • 07/25/2026
In the Linux kernel, the following vulnerability has been resolved:
crypto: caam - use print_hex_dump_devel to guard key hex dumps
Use print_hex_dump_devel() for dumping sensitive key material in *_setkey() and gen_split_key() to avoid leaking secrets at runtime when CONFIG_DYNAMIC_DEBUG is enabled.
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Analysis
by VulDB Data Team • 07/25/2026
The vulnerability addressed in this Linux kernel security update relates to improper handling of sensitive cryptographic key material during debugging operations. When the caam crypto driver was configured with dynamic debugging enabled through CONFIG_DYNAMIC_DEBUG, it would output hexadecimal representations of cryptographic keys to kernel logs using inappropriate debug functions. This creates a significant information disclosure risk where attackers could potentially access sensitive key data through kernel log inspection, particularly in environments where debug output is not properly secured or restricted.
The technical flaw stems from the use of inadequate debugging functions that do not properly guard sensitive data exposure. Specifically, the cryptographic key material was being dumped using standard print functions instead of specialized secure debugging utilities. The caam driver's *_setkey() and gen_split_key() functions were directly utilizing debug output mechanisms that would reveal complete key contents when dynamic debugging was enabled, creating an attack vector through kernel log enumeration.
This vulnerability has substantial operational impact within security-critical environments where cryptographic operations are performed. The exposure of cryptographic keys through kernel logs can lead to complete compromise of encrypted data and authentication systems that rely on these keys. Attackers with access to kernel logs or system monitoring tools could extract key material from debug output, potentially enabling decryption of sensitive communications or impersonation attacks against cryptographic systems.
The mitigation implemented involves replacing standard debugging dump functions with print_hex_dump_devel() which provides enhanced protection for sensitive data. This function properly guards against key material exposure by ensuring that sensitive information is not printed to kernel logs when dynamic debugging is enabled. The solution aligns with security best practices outlined in CWE-200, which addresses information exposure through improper debugging output. Additionally, this remediation supports ATT&CK technique T1562.001 by addressing the improper privilege escalation through debug information exposure and helps prevent information disclosure attacks that could compromise cryptographic systems. The change ensures that even when CONFIG_DYNAMIC_DEBUG is enabled, sensitive key material remains protected from unauthorized access through kernel log channels.
The fix demonstrates proper secure coding practices for cryptographic implementations by implementing appropriate data sanitization and output protection mechanisms. It represents a defensive programming approach that prevents accidental exposure of sensitive information through debugging interfaces while maintaining the ability to debug system operations when necessary. This vulnerability resolution reinforces the principle of least privilege in system debugging operations and addresses potential attack vectors that could be exploited through kernel log enumeration techniques.