{"id":"CVE-2021-22566","aliases":["EUVD-2021-9705","GHSA-q77g-rg5g-rf78"],"status":"published","title":"Incorrect mapping of Executable bits in Fuchsia Kernel","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.","severity":{"version":"4.0","score":5.1,"vector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.00304,"percentile":0.23489,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-275","CWE-287","CWE-732"],"published":"2022-01-18T14:10:10Z","modified":"2026-06-17T03:37:26Z","products":[{"vendor":"google","product":"fuchsia"},{"vendor":"google llc","product":"fuchsia"}],"references":[{"url":"https://fuchsia.googlesource.com/fuchsia/+/7d731b4e9599088ac3073956933559da7bca6a00","tags":["x_refsource_MISC","x_transferred","Mailing List","Patch","Third Party Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-22566"},{"url":"https://github.com/advisories/GHSA-q77g-rg5g-rf78"}],"sources":{"cve":[{"id":"CVE-2021-22566","title":"Incorrect mapping of Executable bits in Fuchsia Kernel","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.","status":"published","published":"2022-01-18T14:10:10Z","modified":"2024-08-03T18:44:14.082Z","cvss":[{"version":"4.0","score":5.1,"vector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N","level":"medium","assessor":"cna"}],"cwes":["CWE-275"],"updated_at":"2026-11-02T14:32:57.701381Z"}],"euvd":[{"id":"EUVD-2021-9705","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.","status":"published","published":"2022-01-18T14:10:10Z","modified":"2024-08-03T18:44:14Z","cvss":[{"version":"4.0","score":5.1,"vector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N","level":"medium"}],"updated_at":"2026-11-03T03:25:02.042856Z"}],"ghsa":[{"id":"GHSA-q77g-rg5g-rf78","title":"An incorrect setting of UXN bits within mmu_flags_to_s1_pte_attr lead to privileged executable...","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.","status":"published","published":"2022-01-19T00:01:22Z","modified":"2023-01-29T05:06:24Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"cwes":["CWE-287","CWE-732"],"updated_at":"2026-11-02T14:46:01.014857Z"}],"nvd":[{"id":"CVE-2021-22566","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.","status":"published","published":"2022-01-18T14:15:07.92Z","modified":"2026-06-17T03:37:26.313Z","cvss":[{"version":"4.0","score":5.1,"vector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"medium","assessor":"secondary"},{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical","assessor":"primary"},{"version":"2.0","score":7.5,"vector":"AV:N/AC:L/Au:N/C:P/I:P/A:P","level":"high","assessor":"primary"}],"cwes":["CWE-275","CWE-732"],"updated_at":"2026-11-02T14:07:03.821385Z"}]}}