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Bug bounty reports15,219

Publicly disclosed HackerOne reports, with the platform's own outcome and severity.

Program:Nextcloud
Status
Severity
Weakness
Year:2026
Clear
Bounty paid21
Access stated
Access needed
Technique
Clear filters63 of 15,219 reports
Disclosed bug bounty reports
ReportStatusWeaknessSeverityDisclosedBountyVotes
No password confirmation required when using apptoken on sensitive endpoint#3566607ValidAccess ControlMedium2026-10-27–2
Unauthenticated Persistent Denial-of-Service via Federated Share Injection#3679640ValidDenial of ServiceHigh2026-10-27–3
Files Confidential tagging can be bypassed with # in filename#3682163ValidAccess ControlMedium2026-10-27–4
Public shares remain accessible via alternate endpoints after owner account is disabled#3620539ValidAccess ControlMedium2026-10-27$2706
Tables application does not respect sharing limitations set by admin#3642236ValidAccess ControlMedium2026-10-27–6
Information disclosure via Desktop client when attempting to lock a file inside a end-to-end encrypted directory#3159877ValidInformation DisclosureNone2026-01-04–8
Unauthorized users can enumerate internal team resources via the Teams API when a team is visible to everyone#3511955ValidAccess ControlMedium2026-10-27–9
Public collectives allow to create pages#3533697ValidAccess ControlLow2026-09-17–9
Unauthorised access with hidden public link creation when sharing to a Team External Member#3625932ValidAccess ControlLow2026-10-27$10011
Code injection allows unprivileged local attacker to execute arbitrary code in Nextcloud's OAuth/web renderer process#3772818ValidCommand and Code InjectionLow2026-10-24–11
Users with read-only access to a Nextcloud Table can enumerate its share recipients via the Tables API#3524971ValidInformation DisclosureLow2026-10-27–12
Cross-room signaling injection enabling unauthorized force-mute#3636758ValidAuthenticationLow2026-10-21–12
Stored XSS in contacts app via organisation and title field#3293290ValidCross-site ScriptingLow2026-01-04$10015
Unauthenticated blind SSRF in Circles signature verification bypasses Nextcloud local-address protections#3303283ValidServer-Side Request ForgeryMedium2026-09-17–15
Shared smart albums in the Photos app can expose files outside the album owner's configured source folders#3506873ValidAccess ControlMedium2026-09-17–16
Activity app does not verify federated file activity received from remote servers#3534050ValidAuthenticationLow2026-09-05$15016
FederationController::remoteWopiToken() returns full Wopi entity without token type validation#3568116ValidAccess ControlLow2026-10-27–17
SSRF on Nextcloud Whiteboard Application via Recordings to Unauthorised Access to Whiteboards#3576823ValidServer-Side Request ForgeryMedium2026-10-27$25017
Path Traversal in Nextcloud Talk Android Exposes User Credentials and Private Data via FileProvider#3696266ValidFile and Path HandlingMedium2026-08-24–18
Deck app allows to spoof file extensions by using RTLO characters#2326618ValidNo weakness recordedMedium2026-01-04$10019
Team membership information returned on API level based on ID#3484601ValidInsecure Direct Object ReferenceLow2026-09-17$20019
Persistent SMTP header injection via identity `organization` / `name`#3913012ValidMemory CorruptionNone2026-09-18–19
Users can modify tags on files that do not belong to them#3040887ValidAccess ControlMedium2026-01-04$15020
Missing Duplicate Check allowing Multiple Retention Rules per System Tag#3521646ValidInput Validation and LogicLow2026-09-05–20
Deck app: Invalid tag color is accepted by API and breaks frontend UI#3485178ValidInput Validation and LogicLow2026-10-20–21
Cross-User Lock/Unlock via Absolute DAV PathAnalysed#3301553ValidAuthenticationMedium2026-09-17–23
Improper Input Validation and Integer Overflow in timeamount parameter of files_retention appAnalysed#3521639ValidMemory CorruptionLow2026-09-05–23
SMTP header injection via C-escape `\r` in the recipient display nameAnalysed#3913007ValidMemory CorruptionNone2026-10-18–23
Predictable proposal participant tokens enable unauthorized access and vote submissionAnalysed#3385434ValidCryptographyLow2026-01-04$10025
Application Data Hiding via Invalid `iconName` Causing Frontend Crash in Nextcloud TablesAnalysed#3508852ValidInput Validation and LogicLow2026-10-20–25
SMIL values and by attributes bypass remote image blocking via unvalidated resource-loading animations, enabling email tracking without consentAnalysed#3590576ValidFile and Path HandlingMedium2026-04-20–26
files_lock: a write-share collaborator can place a TYPE_TOKEN lock that permanently denies the file owner, survives share revocation and account deletAnalysed#3770482ValidAccess ControlMedium2026-09-18–31
Email Enumeration via Password-Protected Share Identity VerificationAnalysed#3507273ValidInformation DisclosureLow2026-09-05$10035
Unquoted body background attribute enables CSS injection that bypasses remote image blockingAnalysed#3590583ValidInjection and SmugglingMedium2026-04-20–35
Critical broken access control: API-only delegated admin can enumerate all Team Folders and grant access to arbitrary groupsAnalysed#3674940ValidAccess ControlMedium2026-09-17–36
Credential Disclosure via Unvalidated directDownloadUrl (Missing DontAddCredentialsAttribute)Analysed#3400143ValidAuthenticationMedium2026-04-13$25037
IDOR on ██████ via direct photo URL leads to unauthorized access to deleted and other users' photos#3518758N/AInsecure Direct Object Reference–2026-04-07–37
Unauthenticated testing endpoint of notify_push expose internal IPAnalysed#3513471ValidInformation DisclosureMedium2026-09-05$15038
Stored XSS in attachment-display exploitable through SameSiteAnalysed#3594137ValidCross-site ScriptingMedium2026-04-19–39
BOLA/IDOR in Out-of-Office API allows any authenticated user to read other users' absence data#3382343InformativeInsecure Direct Object ReferenceMedium2026-04-14–40
Unauthenticated SSRF via Public Reference API -Sharing Token Bypass#3479692InformativeNo weakness recorded–2026-03-31–41
position: fixed !important bypasses CSS sanitizer's fixed-position mitigation, enabling full-viewport phishing overlays.Analysed#3590586ValidInjection and SmugglingMedium2026-04-20–44
Roundcube Webmail Style Sanitizer can be bypassed using CSS Character EscapesAnalysed#3443563ValidInformation DisclosureMedium2026-01-14–46
Can download files on Android app without permissionAnalysed#2380133ValidAccess ControlLow2026-01-16$25047
Mail stored HTML injection in subject textAnalysed#3357036ValidNo weakness recordedMedium2026-02-12–48
SSRF via User-Controlled Push proxyServer in Notifications Push RegistrationAnalysed#3623149ValidServer-Side Request ForgeryMedium2026-09-30–48
SVG filter primitives bypass remote image blocking, enabling email tracking without consent.Analysed#3486747ValidInformation DisclosureMedium2026-04-20–53
Authentication Bypass in ID4me handling via Missing JWT Signature Verification in User OIDCAnalysed#3489490ValidAuthenticationHigh2026-06-07$2,50055
Easy way to create a new Deck board without permissionAnalysed#2388183ValidAccess Control–2026-01-16$10056
Files drop share links for end-to-end encrypted folders allowed to drop files into other folders of the share ownerAnalysed#3304830ValidInsecure Direct Object ReferenceLow2026-05-08–60

Status and severity are HackerOne's. “Access stated” is what the title says; “Access needed” and techniques come from CyberSIXT's analysis of the public report (3,935 analysed so far), which can be wrong. Data as of 2026-11-15.