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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
Bounty paid132
Access stated
Access needed
Technique
Clear filters613 of 15,219 reports
Disclosed bug bounty reports
ReportStatusWeaknessSeverityDisclosedBountyVotes
Access Control: Inject tasks into other users decks#867052ValidAccess ControlMedium2021-02-02–15
Exposing debug.log file leads to server full path disclosure#696360ValidInformation DisclosureLow2019-10-17–15
Non-admin users can trigger writes to memcached by entering a malicious server as a share URL#592864ValidInjection and SmugglingMedium2020-07-09$10015
Email Spoofing Vulnerability from nextcloud.#229599SpamNo weakness recorded–2017-05-18–15
Blind SSRF as normal user from mailapp#1913095ValidServer-Side Request ForgeryLow2023-05-30–14
Reference caching can leak data to unauthorized users#1767503ValidInformation DisclosureMedium2023-01-13–14
bypass forced password protection via circles app#1406926ValidInput Validation and LogicLow2022-06-19$10014
Virtual Data Room / Hide download on collabora is easy to bypass#1194606ValidAccess ControlHigh2021-08-07$15014
Android app does not clear end to end encryption keys#1189168ValidNo weakness recordedLow2021-06-16$10014
Content Spoofing /Text Injection in https://docs.nextcloud.com#666557ValidMisconfiguration and Insecure DesignLow2019-09-05–14
Delete permission can be added on reshare#633245ValidAccess ControlLow2019-09-03–14
Linux client is vulnerable to directory traversal when downloading files#590319ValidFile and Path HandlingMedium2020-08-17$25014
Combination of content provider allows private data disclosure#534541ValidAccess ControlLow2019-07-26$10014
Nextcloud domain and name of every user leaked to lookup server#508490ValidInformation DisclosureMedium2019-11-26–14
Stored XSS in OAuth redirect URI#261138ValidCross-site Scripting–2019-05-11–14
Unauthenticated Stored xss#168054N/ACross-site Scripting–2016-09-13–14
Nextcloud 10.0 privilege escalation issue - Normal user can mask external storage shared by admin#165229ValidAccess Control–2020-03-01–14
Nextcloud Tables v1 Share Enumeration Without Authorization (Regression of CVE-2024-52507)#3334165ValidAuthenticationLow2025-12-05–13
Reflected XSS vulnerability with full CSP bypass in Nextcloud installations using recommended bundle#1893186ValidCross-site ScriptingMedium2023-05-15–13
Mail app - blind SSRF via imapHost parameter#1736390ValidServer-Side Request ForgeryLow2023-02-06–13
Secure view trivial to bypass#1724021ValidAccess ControlMedium2023-03-30$15013
Desktop client can be tricked into opening/executing local files when clicking a nc://open/ link#1720043ValidCommand and Code InjectionMedium2023-02-10–13
Database resource exhaustion for logged-in users via sharee recommendations with circles#1688199ValidDenial of ServiceMedium2022-11-26$25013
Desktop client does not verify received singed certificate in end to end encryption#1679267ValidCryptographyMedium2023-04-27$1,00013
Nextcloud Deck : Possibility for anyone to add a stack with existing tasks on anyone's board#1450117ValidInsecure Direct Object ReferenceMedium2022-05-20–13
End to end encryption public key is not properly verified on Desktop and Android#1189162ValidNo weakness recordedMedium2021-09-23$1,50013
Stored XSS in markdown file with Nextcloud Talk using Internet Explorer#1023787ValidCross-site ScriptingLow2021-02-19–13
Only the file extensions are checked, not the MIME types as configured#697959ValidNo weakness recordedMedium2020-03-14–13
Bypassing lock protection#490946ValidAuthenticationLow2019-07-26$5013
Talk / spreed: Disclosure of Room names and participants for password protected rooms#428010ValidInformation DisclosureMedium2019-04-17$5013
Content Spoofing/Text Injection in https://demo.nextcloud.com#222058ValidMisconfiguration and Insecure Design–2017-04-28–13
Design Issues on ( ███ ) Lead to show ( IPS of Users )#218733ValidNo weakness recorded–2017-04-05–13
Cross-room signaling injection enabling unauthorized force-mute#3636758ValidAuthenticationLow2026-10-21–12
Users with read-only access to a Nextcloud Table can enumerate its share recipients via the Tables API#3524971ValidInformation DisclosureLow2026-10-27–12
Text does not respect 'Allow download' permissions#1965156ValidAccess ControlLow2023-08-23$25012
No password length restriction in reset password endpoint#1820864ValidDenial of ServiceLow2023-02-09–12
Mail app stores cleartext password in database until OAUTH2 setup is done#1806275ValidAuthenticationLow2023-03-08–12
Information exposure in in guzzlehttp/guzzle (https://github.com/nextcloud/3rdparty/tree/master/guzzlehttp/guzzle)#1604606ValidInformation DisclosureLow2022-09-16–12
Lack of Brute force protection while joining video call in talk section which is password protected#1596673ValidInformation DisclosureLow2022-08-08–12
Missing character limitation allows to put generate a database error#1596059ValidDenial of ServiceLow2023-01-09–12
Missing length validation of user displayname allows to generate an SQL error#1588562ValidDenial of ServiceLow2022-12-20–12
Access to arbitrary file of the Nextcloud Android app from within the Nextcloud Android app#1408692ValidFile and Path HandlingLow2022-09-11$25012
Federated share accepting/declining is not logged in audit log#1200815ValidInput Validation and LogicLow2022-09-03–12
Trusted servers exchange can be triggered by attacker#1167853ValidAccess ControlMedium2021-06-10$75012
XSS in image metadata field#896511ValidCross-site ScriptingMedium2020-08-05–12
Able to bypass "Device credentials" Lock#507172ValidAccess ControlLow2019-07-26–12
Predictable Random Number Generator#504731InformativeCryptographyMedium2019-06-26–12
Remote attacker can impersonate Social users via ActivityPub API#461308ValidDeserialization and Object Injection–2019-02-01–12
https://portal.nextcloud.com/.htaccess file is readable#220946ValidInformation Disclosure–2017-04-14–12
Wordpress 4.7.1#201489ValidNo weakness recorded–2017-01-27–12

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 (1,443 analysed so far), which can be wrong. Data as of 2026-11-14.