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Bug bounty reports15,219

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

Program:Nextcloud
Status:Valid
Clear
Severity
Weakness
Year
Bounty paid132
Access stated
Access needed
Technique
Clear filters517 of 15,219 reports
Disclosed bug bounty reports
ReportStatusWeaknessSeverityDisclosedBountyVotes
Stored XSS on Share-popup of a directory's Gallery-viewAnalysed#145355ValidCross-site Scripting–2016-07-19–24
SMTP header injection via C-escape `\r` in the recipient display nameAnalysed#3913007ValidMemory CorruptionNone2026-10-18–23
Improper Input Validation and Integer Overflow in timeamount parameter of files_retention appAnalysed#3521639ValidMemory CorruptionLow2026-09-05–23
Cross-User Lock/Unlock via Absolute DAV PathAnalysed#3301553ValidAuthenticationMedium2026-09-17–23
User scoped external storage can be used to gather credentials of other usersAnalysed#1978882ValidInput Validation and LogicHigh2023-06-27–23
Improper restriction of excessive authentication attempts on WebDAV endpointAnalysed#1924212ValidAuthenticationMedium2023-08-10–23
Session fixation on public talk linksAnalysed#1181962ValidAuthenticationMedium2021-06-16$10023
Ratelimiting can be bypassed using IPv6 subnetsAnalysed#1154003ValidAuthenticationLow2021-07-01–23
Possible denial of service when entering a loooong passwordAnalysed#840598ValidAuthenticationMedium2020-07-29$10023
Persistent XSS via filename in projectsAnalysed#662204ValidCross-site ScriptingLow2020-03-01$15023
Calendar attachments of local files are offered to downloadedAnalysed#3112033ValidInput Validation and LogicMedium2025-12-05–22
Improper handling of request URLs in nextcloud/guests allows guest users to bypass app allowlistAnalysed#2251074ValidInjection and SmugglingMedium2024-01-18–22
SMTP Command Injection in iCalendar Attachments to Emails via NewlinesAnalysed#1516377ValidInjection and SmugglingMedium2022-07-04–22
Lack of bruteforce protection for TOTP 2FAAnalysed#1265709ValidAuthenticationMedium2023-03-26$75022
XSS through image upload of contacts using svg fileAnalysed#894876ValidCross-site ScriptingLow2020-12-17$10022
"Secure View" aka "Hide Download" can be bypassed easilyAnalysed#788257ValidAccess ControlHigh2020-04-10–22
Gallery: No feedback for invalid passwordAnalysed#428660ValidInput Validation and LogicLow2019-07-27$5022
Deck app: Invalid tag color is accepted by API and breaks frontend UIAnalysed#3485178ValidInput Validation and LogicLow2026-10-20–21
Open redirect in user_saml via RelayState parameterAnalysed#2263044ValidOpen RedirectLow2024-01-18–21
Full Passcode bypass on Nextcloud App iOSAnalysed#1847368ValidAccess ControlLow2023-04-10–21
Possibility to delete files attached to deck cards of other usersAnalysed#1755555ValidInsecure Direct Object ReferenceLow2023-01-09–21
Notification implicit PendingIntent in com.nextcloud.client allows to access contactsAnalysed#1161401ValidInformation DisclosureLow2022-05-27$25021
XSS through image upload of contacts using svg file with png extensionAnalysed#998422ValidCross-site ScriptingLow2020-12-26–21
Missing Duplicate Check allowing Multiple Retention Rules per System TagAnalysed#3521646ValidInput Validation and LogicLow2026-09-05–20
Users can modify tags on files that do not belong to themAnalysed#3040887ValidAccess ControlMedium2026-01-04$15020
Self XSS when pasting HTML into Text app with Ctrl+Shift+VAnalysed#2211561ValidCross-site ScriptingMedium2023-12-21–20
Self XSS when sending HTML as a comment in the Deck appAnalysed#2058556ValidCross-site ScriptingNone2024-01-18–20
[user_oidc] Unencrypted CommunicationsAnalysed#1687005ValidCryptographyLow2022-12-18–20
Missing brute force protection on OAuth2 API controllerAnalysed#1258448ValidAuthenticationMedium2023-08-10$50020
Sensitive files/ data exists post deletion of user accountAnalysed#1222873ValidAccess ControlLow2022-05-20–20
Access control missing while viewing the attachments in the "All boards"Analysed#916704ValidInsecure Direct Object ReferenceMedium2020-09-29$15020
Denial of Service by requesting to reset a passwordAnalysed#812754ValidDenial of ServiceHigh2021-01-25–20
Username and Access Token DisclousureAnalysed#672623ValidMisconfiguration and Insecure DesignLow2020-03-01$25020
OAuth2 Access Token and App Password Security VulnerabilityAnalysed#343111ValidCryptographyMedium2018-07-21–20
bypass of 2FAAnalysed#248656ValidAuthenticationHigh2018-07-29$75020
Session fixation in password protected public download.Analysed#237184ValidAuthenticationLow2018-10-25–20
https://xmpp.nextcloud.com///;@www.google.com allows open redirectAnalysed#211213ValidOpen Redirect–2017-08-13–20
Persistent SMTP header injection via identity `organization` / `name`Analysed#3913012ValidMemory CorruptionNone2026-09-18–19
Team membership information returned on API level based on IDAnalysed#3484601ValidInsecure Direct Object ReferenceLow2026-09-17$20019
Deck app allows to spoof file extensions by using RTLO charactersAnalysed#2326618ValidNo weakness recordedMedium2026-01-04$10019
Memcached used as RateLimiter backend is no-opAnalysed#2110945ValidAuthenticationMedium2023-11-12–19
Missing permission check when removing a photo from an albumAnalysed#1946298ValidAccess ControlLow2024-07-14–19
[user_oidc] Stored XSS via Authorization Endpoint - Safari-OnlyAnalysed#1687410ValidCross-site ScriptingLow2022-12-18–19
Talk Android broadcast receiver is not protected by broadcastPermission allowing malicious apps to communicateAnalysed#1596459ValidAccess ControlLow2022-12-25–19
When sharing a Deck card in conversation the metaData can be manipulated to open arbitrary URLAnalysed#1358977ValidInput Validation and LogicMedium2022-02-15–19
SQLi allow query restriction bypass on exposed FileContentProviderAnalysed#518669ValidSQL InjectionLow2019-07-29$10019
Authentication IssueAnalysed#146133ValidAuthentication–2018-10-25$5019
Path Traversal in Nextcloud Talk Android Exposes User Credentials and Private Data via FileProviderAnalysed#3696266ValidFile and Path HandlingMedium2026-08-24–18
see card comments after remove shared boardAnalysed#2289333ValidAccess ControlMedium2024-06-18–18
App pin of the Android app can be bypassed via 3rdparty apps generating deep linksAnalysed#1825679ValidAuthenticationLow2023-05-04–18

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, where there is one, which can be wrong. Data as of 2026-11-15.