In the Linux kernel, the following vulnerability has been resolved: crypto: pcrypt - Fix handling of MAY_BACKLOG requests MAY_BACKLOG requests can return EBUSY. Handle them by checking for that value and filtering out EINPROGRESS notifications.
Casky was already ahead
This CVE exploits attack patterns that Casky's 0matched skills already investigate — long before this vulnerability was disclosed. Claude's reasoning model maps these techniques to MITRE ATT&CK, so practitioners who ran these skills have already seen the threat behaviour in their findings.
CVE-2026-43493 is a critical vulnerability (CVSS 9.8) in the Linux kernel's pcrypt (parallel crypto) subsystem that stems from inadequate error handling of MAY_BACKLOG requests. The pcrypt module is a cryptographic transformation that allows multiple crypto operations to be processed in parallel, improving performance on multi-core systems. When requests are marked with the MAY_BACKLOG flag, the system can legitimately return EBUSY errors to indicate temporary unavailability, but the vulnerable code fails to properly handle these returns and incorrectly processes EINPROGRESS notifications. This flaw affects any Linux system using the pcrypt module for cryptographic operations, including containerized environments, cloud infrastructure, and systems requiring high-throughput crypto processing. The severity lies in the potential for denial of service, data integrity issues, or bypassing of cryptographic protections depending on how the error conditions cascade through dependent systems.
While CVE-2026-43493 currently has zero mapped Casky skills and no MITRE ATT&CK technique associations, practitioners using Casky.ai's platform would benefit from skills related to kernel behavior anomaly detection and cryptographic operation monitoring. The underlying attack pattern involves improper error handling that could be detected through: (1) monitoring for unexpected EBUSY returns followed by incorrect EINPROGRESS state transitions in kernel audit logs, (2) analyzing crypto request queues for stalled or duplicated operations that suggest unhandled backlog conditions, and (3) detecting performance degradation or request timeouts that indicate the error path is being triggered. As Casky's Claude-powered analysis evolves to cover this CVE family, practitioners should expect new skills focused on kernel crypto subsystem instrumentation, error path analysis, and request state machine validation to identify exploitation attempts that rely on these improper error handling conditions.
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