{"id":"CVE-2026-65400","kind":"vulnerability","aliases":["CVE-2026-65400"],"related":[],"title":"apple macos: An authentication issue was addressed with improved state management","description":"Apple macOS contains an improper authentication vulnerability that could allow an attacker on the network to authenticate to Screen Sharing without valid credentials.\n\nCISA required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.","summary":"macOS Screen Sharing can be reached over the network and accepts a login without valid credentials. An attacker who reaches the Screen Sharing service can take control of the Mac's screen and input.","severity":"critical","cvss":9.8,"epss":null,"exploited":true,"exploited_at":"2026-08-18T00:00:00+00:00","products":[{"name":"Apple macOS","fixed":["14.8.9","15.7.9","26.6.1","26.7","27"],"affected":"< 14.8.9 (Sonoma), < 15.7.9 (Sequoia), < 26.6.1 (Tahoe)","ecosystem":"vendor"},{"name":"apple macos","fixed":["14.8.9"],"affected":">= 14.0, < 14.8.9","ecosystem":"vendor"},{"name":"apple macos","fixed":["15.7.9"],"affected":">= 15.0, < 15.7.9","ecosystem":"vendor"},{"name":"apple macos","fixed":["26.6.1"],"affected":">= 26.0, < 26.6.1","ecosystem":"vendor"},{"name":"Apple macOS","fixed":[],"affected":"","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["cisa-kev","exploited","mac-fleet","macos","poc-public","screen-sharing","self-hosted","vendor"],"not_affected_if":["screen-sharing-off"],"how_to_check":"Check System Settings > General > Sharing: Screen Sharing is off or restricted to named users. Confirm the macOS version with sw_vers against the fixed builds.","fix":"Update to macOS Tahoe 26.6.1, Sequoia 15.7.9, Sonoma 14.8.9, or later. Until patched, turn off Screen Sharing or block its port from untrusted networks.","status":"open","published_at":"2026-08-06T22:18:14+00:00","first_seen_at":"2026-10-23T19:11:51+00:00","triaged_at":"2026-10-23T22:42:15+00:00","updated_at":"2026-10-24T00:09:50+00:00","category":"vendor","confidence":0.8,"triage":{"at":"2026-10-23T22:42:15Z","model":"claude-haiku-5-5","output":{"fix":"Update to macOS Tahoe 26.6.1, Sequoia 15.7.9, Sonoma 14.8.9, or later. Until patched, turn off Screen Sharing or block its port from untrusted networks.","reach":"network","title":"Apple macOS: improper authentication lets network attackers into Screen Sharing","impact":"high","summary":"macOS Screen Sharing can be reached over the network and accepts a login without valid credentials. An attacker who reaches the Screen Sharing service can take control of the Mac's screen and input.","category":"vendor","nicknames":["Calif: No Country for Old Passwords"],"who_cares":["macos","mac-fleet","screen-sharing","self-hosted"],"confidence":0.8,"needs_auth":"no","worst_case":"Attacker gets remote screen control of the Mac without credentials.","analyst_note":"Confirm the exact exploit conditions and whether Screen Sharing must be enabled, via the Ars Technica and NCSC-NL write-ups and Apple's Tahoe 26.6.1 security content.","how_to_check":"Check System Settings > General > Sharing: Screen Sharing is off or restricted to named users. Confirm the macOS version with sw_vers against the fixed builds.\nunknown","needs_analyst":true,"not_affected_if":["screen-sharing-off"],"user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"critical"},"cost_usd":0.000605,"input_tokens":3531,"output_tokens":503,"severity_before":"critical"},"analyst_status":"done","analyst_note":"Find Apple's security advisory for CVE-2026-65400 to confirm affected and fixed macOS versions and the exact Screen Sharing mitigation; check the CISA KEV entry for the due date.","search":"'-04':126C,152C,183C '-2026':13A,16A '-65400':14A,17A '26':125C,151C,182C 'accept':62B 'accord':115C 'action':111C 'address':7A 'adher':179C 'allow':95C 'appl':1A,86C 'apple':24A,26A,28A,30A,32A 'appli':112C 'applic':149C 'asset':173C 'attack':69B,97C 'authent':4A,91C,102C 'base':130C 'bod':124C,150C,181C 'calif':18A 'cisa':35B,109C,122C,139C 'cisa-kev':34B 'cloud':155C 'complianc':120C 'contain':88C 'control':78B 'could':94C 'country':20A 'credenti':67B,108C 'cve':12A,15A 'discontinu':158C 'ensur':119C,178C 'evalu':171C 'exploit':37B 'exposur':176C 'fleet':40B 'follow':148C 'for':21A 'forens':141C 'guidanc':137C,153C 'guidelin':185C 'host':50B 'improp':90C 'improv':9A 'input':85B 'instruct':118C 'internet':175C 'issu':5A 'kev':36B 'login':64B 'mac':39B,81B 'mac-fleet':38B 'maco':2A,41B,52B,87C 'macos':25A,27A,29A,31A,33A 'manag':11A 'mitig':113C,164C 'network':60B,100C 'no':19A 'note':136C,147C 'old':22A 'passwords':23A 'patch':184C 'poc':43B 'poc-publ':42B 'priorit':127C 'product':162C 'public':44B 'reach':57B,71B 'requir':110C,143C 'respons':169C 'risk':132C 'screen':46B,53B,73B,83B,104C 'screen-shar':45B 'secur':128C 'see':133C,144C 'self':49B 'self-host':48B 'servic':75B,156C 'share':47B,54B,74B,105C 'stakehold':167C 'state':10A 'take':77B 'triag':142C 'unavail':166C 'updat':129C 'url':134C,145C 'use':159C 'valid':66B,107C 'vendor':51B,117C 'vulner':92C 'without':65B,106C","nicknames":["Calif: No Country for Old Passwords"],"mitigations":[],"who_affected":null,"tier":null,"verified":{},"analyst_revisit_at":null,"first_public_at":"2026-08-06T22:18:14+00:00","kev":{"dateAdded":"2026-08-18","dueDate":"2026-08-21","requiredAction":"Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.","knownRansomwareCampaignUse":"Unknown"},"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cvss_by":"134c704f-9b21-4f2e-91b3-4a467353bcc0","poc_count":1,"sources":[{"source":"kev","external_id":"CVE-2026-65400","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2026-65400","severity":null,"published_at":"2026-08-18T00:00:00+00:00","modified_at":null,"first_seen_at":"2026-10-23T19:11:51+00:00","fetched_at":"2026-10-25T12:39:21+00:00","note":null},{"source":"analyst","external_id":"CVE-2026-65400:131","url":null,"severity":null,"published_at":"2026-10-23T21:41:27+00:00","modified_at":"2026-10-23T21:41:27+00:00","first_seen_at":"2026-10-23T21:41:27+00:00","fetched_at":"2026-10-23T21:41:27+00:00","note":"Apple advisories (Sequoia 15.7.9, Tahoe 26.6.1, released 2026-08-06) confirm fix; NVD/CVE.org list Sonoma 14.8.9, Tahoe 26.7, macOS 27 as fixed too (Sonoma/26.7/27 Apple pages not read). KEV added 2026-08-18, due 2026-08-21. Exploited (NCSC-NL: port 5900 exposed, root, Monero miner); public PoCs exist (panchocosil read-only; others write/RCE, one repo looks untrustworthy). CVSS 9.8 CNA; Ars cites 7.1. X/Bluesky not searched."},{"source":"nvd","external_id":"CVE-2026-65400","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-65400","severity":null,"published_at":"2026-08-06T22:18:14+00:00","modified_at":"2026-10-23T21:10:00+00:00","first_seen_at":"2026-10-23T23:44:51+00:00","fetched_at":"2026-10-23T23:44:51+00:00","note":null}],"documents":[{"id":1197,"url":"https://support.apple.com/en-us/148171","title":"Apple: macOS Sequoia 15.7.9 security content","kind":"advisory","source":"analyst","text":null,"published_at":null,"relation":"advisory","confidence":null,"note":null},{"id":1199,"url":"https://support.apple.com/en-us/148170","title":"Apple: macOS Tahoe 26.6.1 security content","kind":"advisory","source":"analyst","text":null,"published_at":null,"relation":"advisory","confidence":null,"note":null},{"id":1200,"url":"https://nvd.nist.gov/vuln/detail/cve-2026-65400","title":"NVD CVE-2026-65400 (KEV due date)","kind":"other","source":"analyst","text":null,"published_at":null,"relation":"describes","confidence":null,"note":null},{"id":1202,"url":"https://arstechnica.com/security/2026/08/vulnerability-giving-attackers-full-control-of-macs-is-under-active-exploitation/","title":"Ars Technica: exploited in the wild, NCSC-NL, Sharing toggle","kind":"blog","source":"analyst","text":null,"published_at":null,"relation":"mitigation","confidence":null,"note":null},{"id":1204,"url":"https://github.com/panchocosil/CVE-2026-65400-poc","title":"panchocosil read-only PoC","kind":"poc","source":"analyst","text":null,"published_at":null,"relation":"poc","confidence":null,"note":null},{"id":1206,"url":"https://blog.calif.io/p/no-country-for-old-passwords","title":"Calif: No Country for Old Passwords (exploit analysis)","kind":"blog","source":"analyst","text":null,"published_at":null,"relation":"discussion","confidence":null,"note":null}],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}