What’s Vulnerable › Vulnerabilities

CVE-2021-22566: Incorrect mapping of Executable bits in Fuchsia Kernel

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2022-01-18 · updated 2026-06-17
• Weakness: CWE-275

Description

An incorrect setting of UXN bits within mmu_flags_to_s1_pte_attr lead to privileged executable pages being mapped as executable from an unprivileged context. This can be leveraged by an attacker to bypass executability restrictions of kernel-mode pages from user-mode. An incorrect setting of PXN bits within mmu_flags_to_s1_pte_attr lead to unprivileged executable pages being mapped as executable from a privileged context. This can be leveraged by an attacker to bypass executability restrictions of user-mode pages from kernel-mode. Typically this allows a potential attacker to circumvent a mitigation, making exploitation of potential kernel-mode vulnerabilities easier. We recommend updating kernel beyond commit 7d731b4e9599088ac3073956933559da7bca6a00 and rebuilding.

Affected products

• Google LLC Fuchsia Kernel: all versions

References

• https://fuchsia.googlesource.com/fuchsia/+/7d731b4e9599088ac3073956933559da7bca6a00
• https://fuchsia.googlesource.com/fuchsia/+/7d731b4e9599088ac3073956933559da7bca6a00

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