Incorrect conditional selection via unmasked register bits
Published Jul 17, 2026 · Updated Jul 17, 2026
Incorrect computation in RustCrypto cmov 0.1.1 through 0.5.3 allows attackers to obtain wrong Cmov or CmovEq results on AArch64 via narrowed inputs. The inline assembly in cmov/src/backends/aarch64.rs compares full registers without masking undefined upper bits of narrow inputs. Manifestation requires calling code to pass a narrowed value whose original high bits remain set; the conditional select can then preserve or move the wrong operand.
Summary
What happened
Incorrect computation in RustCrypto cmov 0.1.1 through 0.5.3 allows attackers to obtain wrong Cmov or CmovEq results on AArch64 via narrowed inputs. The inline assembly in cmov/src/backends/aarch64.rs compares full registers without masking undefined upper bits of narrow inputs. Manifestation requires calling code to pass a narrowed value whose original high bits remain set; the conditional select can then preserve or move the wrong operand.
The record
- CVE
- CVE-2026-50185
- Published
- Jul 17, 2026
- Updated
- Jul 17, 2026
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-758
- Attack vector
- local
- Privileges
- Unavailable
Timeline
How it unfolded
- Jul 17, 2026CVE publishedPublication date reported by the CVE source.
- Jul 17, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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What is affected?
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Published CVSS scores
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Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
- AArch64 Cmov and CmovEq failing test casesproof of concept · demonstrated
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Technologies
Your stack
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