{"id":"CVE-2026-111921","kind":"vulnerability","aliases":["CVE-2026-111921"],"related":[],"title":"Vikunja: project writers can delete admin-tier link shares","description":"Vikunja 0.13.0 before 2.7.0 contains an incorrect authorization vulnerability that allows project members with Write permission to delete admin-tier link shares because the delete permission check reads an unloaded share object. Attackers can send DELETE requests to the v1 or v2 projects shares endpoints with sequential share IDs to revoke admin links and invalidate existing share sessions.","summary":"Vikunja versions from 0.13.0 before 2.7.0 let a project member with Write permission delete admin-level link shares, because the delete permission check reads an unloaded share object. An attacker can send DELETE requests to the projects shares endpoints with sequential share IDs to revoke admin links and invalidate existing share sessions.","severity":"medium","cvss":5.4,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["package","project-management","self-hosted","vikunja"],"not_affected_if":["read-only-project-members","versions-2.7.0-or-later"],"how_to_check":"- Check the running Vikunja version with `vikunja version` or the server build info; affected if it is `0.13.0` up to but not including `2.7.0`\n- Review which project members hold Write permission and whether any link shares were removed unexpectedly","fix":"- Upgrade Vikunja to `2.7.0` or later\n- Re-issue any link shares that were revoked and rotate share sessions if unexpected deletions are found","status":"open","published_at":"2026-10-17T19:16:34+00:00","first_seen_at":"2026-10-23T21:57:14+00:00","triaged_at":"2026-10-25T04:16:56+00:00","updated_at":"2026-10-25T04:16:56+00:00","category":"package","confidence":0.7,"triage":{"at":"2026-10-25T04:16:56Z","model":"claude-haiku-5-5","output":{"fix":"- Upgrade Vikunja to `2.7.0` or later\n- Re-issue any link shares that were revoked and rotate share sessions if unexpected deletions are found","reach":"network","title":"Vikunja: project writers can delete admin-tier link shares","impact":"medium","summary":"Vikunja versions from 0.13.0 before 2.7.0 let a project member with Write permission delete admin-level link shares, because the delete permission check reads an unloaded share object. An attacker can send DELETE requests to the projects shares endpoints with sequential share IDs to revoke admin links and invalidate existing share sessions.","category":"package","nicknames":[],"who_cares":["vikunja","self-hosted","project-management"],"confidence":0.7,"needs_auth":"yes","worst_case":"A project writer revokes admin link shares and invalidates share sessions","analyst_note":"","how_to_check":"- Check the running Vikunja version with `vikunja version` or the server build info; affected if it is `0.13.0` up to but not including `2.7.0`\n- Review which project members hold Write permission and whether any link shares were removed unexpectedly","needs_analyst":false,"not_affected_if":["versions-2.7.0-or-later","read-only-project-members"],"who_is_affected":"Self-hosted or managed Vikunja instances on versions from 0.13.0 up to 2.7.0 where some users hold Write permission on projects that have admin-tier link shares. Instances where every user is an admin or only read access is granted to project members are less exposed. The sources do not say whether the flaw is reachable without an account, but the attacker must already be a project member with Write permission.","user_interaction":"no","needs_special_setup":"no","severity_if_unknown":"medium"},"cost_usd":0.000634,"input_tokens":3353,"output_tokens":598,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-111921':13A,16A '-2026':12A,15A '0.13.0':28B,79C '2.7.0':30B,81C 'admin':7A,40B,71B,97C,130C 'admin-level':39B 'admin-ti':6A,96C 'allow':88C 'attack':55B,111C 'author':85C 'check':48B,105C 'contain':82C 'cve':11A,14A 'delet':5A,38B,46B,58B,95C,103C,114C 'endpoint':64B,123C 'exist':75B,134C 'host':23B 'id':68B,127C 'incorrect':84C 'invalid':74B,133C 'let':31B 'level':41B 'link':9A,42B,72B,99C,131C 'manag':20B 'member':34B,90C 'object':53B,110C 'packag':17B 'permiss':37B,47B,93C,104C 'project':2A,19B,33B,62B,89C,121C 'project-manag':18B 'read':49B,106C 'request':59B,115C 'revok':70B,129C 'self':22B 'self-host':21B 'send':57B,113C 'sequenti':66B,125C 'session':77B,136C 'share':10A,43B,52B,63B,67B,76B,100C,109C,122C,126C,135C 'tier':8A,98C 'unload':51B,108C 'v1':118C 'v2':120C 'version':26B 'vikunja':1A,24B,25B,78C 'vulner':86C 'write':36B,92C 'writer':3A","nicknames":[],"mitigations":[],"who_affected":"Self-hosted or managed Vikunja instances on versions from 0.13.0 up to 2.7.0 where some users hold Write permission on projects that have admin-tier link shares. Instances where every user is an admin or only read access is granted to project members are less exposed. The sources do not say whether the flaw is reachable without an account, but the attacker must already be a project member with Write permission.","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:L/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-2026-111921","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-111921","severity":null,"published_at":"2026-10-17T19:16:34+00:00","modified_at":"2026-10-21T22:16:48+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"}