{"id":"CVE-2026-111920","kind":"vulnerability","aliases":["CVE-2026-111920"],"related":[],"title":"Vikunja: parent project write access overrides read-only child project shares","description":"Vikunja 2.6.0 contains a broken access control flaw in getProjectAccessForUser (pkg/models/project_access.go), which resolves a user's effective project permission as the maximum over the project tree, silently overriding explicit lower-permission shares on sub-projects. A collaborator with write access on a parent project but read-only access to a child project can modify the child project's tasks and content.","summary":"Vikunja 2.6.0 resolves a user's project permission as the maximum across the project tree, so an explicit read-only share on a sub-project is overridden. A collaborator with write access to the parent project can modify tasks and content in the read-only child project.","severity":"medium","cvss":5.3,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["package","self-hosted","vikunja"],"not_affected_if":["no-sub-projects","single-user"],"how_to_check":null,"fix":null,"status":"open","published_at":"2026-10-17T19:16:34+00:00","first_seen_at":"2026-10-23T21:57:14+00:00","triaged_at":"2026-10-25T04:26:50+00:00","updated_at":"2026-10-25T04:26:50+00:00","category":"package","confidence":0.6,"triage":{"at":"2026-10-25T04:26:50Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"internet","title":"Vikunja: parent project write access overrides read-only child project shares","impact":"medium","summary":"Vikunja 2.6.0 resolves a user's project permission as the maximum across the project tree, so an explicit read-only share on a sub-project is overridden. A collaborator with write access to the parent project can modify tasks and content in the read-only child project.","category":"package","nicknames":[],"who_cares":["vikunja","self-hosted"],"confidence":0.6,"needs_auth":"yes","worst_case":"A collaborator modifies tasks in a read-only child project.","analyst_note":"Sources list only the NVD entry; check the Vikunja advisory or fixed release version for the fix and the exact affected range.","how_to_check":"unknown","needs_analyst":true,"not_affected_if":["single-user","no-sub-projects"],"who_is_affected":"Teams running Vikunja 2.6.0 that share parent projects with collaborators and use read-only shares on sub-projects. Installations that do not use nested projects with mixed sharing levels are unlikely to be exposed. Instances on other versions are not covered by the sources.","user_interaction":"no","needs_special_setup":"no","severity_if_unknown":"medium"},"cost_usd":0.000553,"input_tokens":3354,"output_tokens":435,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-111920':15A,18A '-2026':14A,17A '2.6.0':25B,75C 'access':5A,57B,79C,115C,124C 'across':35B 'broken':78C 'child':10A,72B,127C,132C 'collabor':54B,112C 'contain':76C 'content':66B,137C 'control':80C 'cve':13A,16A 'effect':90C 'explicit':41B,102C 'flaw':81C 'getprojectaccessforus':83C 'host':22B 'lower':104C 'lower-permiss':103C 'maximum':34B,95C 'modifi':63B,130C 'overrid':6A,101C 'overridden':52B 'packag':19B 'parent':2A,60B,118C 'permiss':31B,92C,105C 'pkg/models/project_access.go':84C 'project':3A,11A,30B,37B,50B,61B,73B,91C,98C,110C,119C,128C,133C 'read':8A,43B,70B,122C 'read-on':7A,42B,69B,121C 'resolv':26B,86C 'self':21B 'self-host':20B 'share':12A,45B,106C 'silent':100C 'sub':49B,109C 'sub-project':48B,108C 'task':64B,135C 'tree':38B,99C 'user':28B,88C 'vikunja':1A,23B,24B,74C 'write':4A,56B,114C","nicknames":[],"mitigations":[],"who_affected":"Teams running Vikunja 2.6.0 that share parent projects with collaborators and use read-only shares on sub-projects. Installations that do not use nested projects with mixed sharing levels are unlikely to be exposed. Instances on other versions are not covered by the sources.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-17T19:16:34+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/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","cvss_by":"disclosure@vulncheck.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-111920","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-111920","severity":null,"published_at":"2026-10-17T19:16:34+00:00","modified_at":"2026-10-19T21:02:51+00:00","first_seen_at":"2026-10-23T21:57:14+00:00","fetched_at":"2026-10-23T22:28:55+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}