iOS, iPadOS, tvOS, watchOS, and macOS contain a double-free vulnerability in the GNU kernel's `lio_listio()` function, which can allow a malicious application to achieve unsandboxed, kernel-level code execution.
\r\n\r\n### Description ###\r\niOS, iPadOS, tvOS, watchOS, and macOS contain an a double-free vulnerability in the GNU kernel's `lio_listio()` function. This can lead to triggering a use-after-free condition. This vulnerability can allow code execution with kernel privileges. This vulnerability is being used by the public unc0ver 5.0 jailbreak utility, which claims to support all devices from iOS 11 through 13.5, excluding versions 12.3-12.3.2 and 12.4.2-12.4.5. It is also reported that this jailbreak works on modern iOS devices that use a CPU that supports Pointer Authentication Code (PAC), which indicates that PAC does not prevent exploitation of this vulnerability.
\r\nIt is reported that this vulnerability is a regression of the vulnerability known as [LightSpeed](https://www.synacktiv.com/posts/exploit/lightspeed-a-race-for-an-iosmacos-sandbox-escape.html).\r\n\r\n### Impact ###\r\nBy convincing a user to run a malicious application on a device running iOS, iPadOS, tvOS, watchOS, or macOS, an attacker may be able to achieve arbitrary code execution in the kernel that is not restricted by sandboxes or other OS protections.\r\n\r\n### Solution ###\r\n#### Apply updates\r\nThis issue is addressed in the following OS updates from Apple: \r\n[macOS Catalina 10.15.5 Supplemental Update, Security Update 2020-003 High Sierra](https://support.apple.com/en-us/HT211215) \r\n[tvOS 13.4.6](https://support.apple.com/en-us/HT211216) \r\n[watchOS 6.2.6](https://support.apple.com/en-us/HT211217) \r\n[iOS 13.5.1 and iPadOS 13.5.1](https://support.apple.com/en-us/HT211214) \r\n\r\n### Acknowledgements ###\r\nThis document was written by Will Dormann.","title":"Summary"},{"category":"legal_disclaimer","text":"THIS DOCUMENT IS PROVIDED ON AN 'AS IS' BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. YOUR USE OF THE INFORMATION ON THE DOCUMENT OR MATERIALS LINKED FROM THE DOCUMENT IS AT YOUR OWN RISK. ","title":"Legal Disclaimer"},{"category":"other","text":"CERT/CC Vulnerability Note is a limited advisory. It primarily identifies vendors impacted by the advisory and not specific products. We only support \"known_affected\" and \"known_not_affected\" status. Please consult the vendor's statements and advisory URL if provided by the vendor for more details ","title":"Limitations of Advisory"},{"category":"other","text":"No statement is currently available from the vendor regarding this vulnerability.","title":"Vendor statment from Apple"},{"category":"other","text":"There are no additional comments at this time.","title":"CERT/CC comment on Apple notes"}],"publisher":{"category":"coordinator","contact_details":"Email: cert@cert.org, Phone: +1412 268 5800","issuing_authority":"CERT/CC under DHS/CISA https://www.cisa.gov/cybersecurity also see https://kb.cert.org/ ","name":"CERT/CC","namespace":"https://kb.cert.org/"},"references":[{"url":"https://certcc.github.io/certcc_disclosure_policy","summary":"CERT/CC vulnerability disclosure policy"},{"summary":"CERT/CC document released","category":"self","url":"https://kb.cert.org/vuls/id/127371"},{"url":"https://support.apple.com/en-us/HT211214","summary":"https://support.apple.com/en-us/HT211214"},{"url":"https://support.apple.com/en-us/HT211215","summary":"https://support.apple.com/en-us/HT211215"},{"url":"https://support.apple.com/en-us/HT211216","summary":"https://support.apple.com/en-us/HT211216"},{"url":"https://support.apple.com/en-us/HT211217","summary":"https://support.apple.com/en-us/HT211217"},{"url":"https://unc0ver.dev/","summary":"https://unc0ver.dev/"},{"url":"https://googleprojectzero.blogspot.com/2020/07/how-to-unc0ver-0-day-in-4-hours-or-less.html","summary":"https://googleprojectzero.blogspot.com/2020/07/how-to-unc0ver-0-day-in-4-hours-or-less.html"},{"url":"https://googleprojectzero.blogspot.com/2019/02/examining-pointer-authentication-on.html","summary":"https://googleprojectzero.blogspot.com/2019/02/examining-pointer-authentication-on.html"},{"url":"https://support.apple.com/en-us/HT211214","summary":"Reference(s) from vendor \"Apple\""},{"url":"https://support.apple.com/en-us/HT211215","summary":"Reference(s) from vendor \"Apple\""},{"url":"https://support.apple.com/en-us/HT211216","summary":"Reference(s) from vendor \"Apple\""},{"url":"https://support.apple.com/en-us/HT211217","summary":"Reference(s) from vendor \"Apple\""}],"title":"iOS, iPadOS, tvOS, watchOS, and macOS contain a double-free vulnerability in the XNU kernel lio_listio() function","tracking":{"current_release_date":"2020-07-09T17:58:43+00:00","generator":{"engine":{"name":"VINCE","version":"3.0.35"}},"id":"VU#127371","initial_release_date":"2020-05-23 00:00:00+00:00","revision_history":[{"date":"2020-07-09T17:58:43+00:00","number":"1.20200709175843.23","summary":"Released on 2020-07-09T17:58:43+00:00"}],"status":"final","version":"1.20200709175843.23"}},"vulnerabilities":[{"title":"iOS, iPadOS, tvOS, watchOS, and macOS contain a kernel memory consumption vulnerability due to flawed memory handling.","notes":[{"category":"summary","text":"iOS, iPadOS, tvOS, watchOS, and macOS contain a kernel memory consumption vulnerability due to flawed memory handling."}],"cve":"CVE-2020-9859","ids":[{"system_name":"CERT/CC V Identifier ","text":"VU#127371"}],"product_status":{"known_affected":["CSAFPID-b21cb3a6-3a7c-11f1-a172-0afffb3ee71d"]}}],"product_tree":{"branches":[{"category":"vendor","name":"Apple","product":{"name":"Apple Products","product_id":"CSAFPID-b21cb3a6-3a7c-11f1-a172-0afffb3ee71d"}}]}}