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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:Input Validation and Logic
Clear
Year
Bounty paid4
Access stated
Access needed
Technique
Clear filters19 of 15,219 reports
Disclosed bug bounty reports
ReportStatusWeaknessSeverityDisclosedBountyVotes
No rate limiting for confirmation email lead to huge Mass mailingsAnalysed#997070ValidInput Validation and LogicMedium2020-11-04–82
Improper input validation in emoji field leads to sidebar UI denial of serviceAnalysed#3599470ValidInput Validation and LogicLow2026-09-20–64
Approval app's file-freshness check can be bypassed by omitting the etag parameter, allowing approval of unreviewed file changesAnalysed#3610332ValidInput Validation and LogicMedium2026-09-17$15063
Notes app can be tricked into using a received share created before the user logged inAnalysed#2254151ValidInput Validation and LogicMedium2024-06-19–49
Exposing debug.log file leads to server full path disclosureAnalysed#2778441ValidInput Validation and LogicMedium2025-09-29–47
Non-admin users can reset app allowlist to the defaultAnalysed#2250398ValidInput Validation and LogicMedium2024-01-18–28
Application Data Hiding via Invalid `iconName` Causing Frontend Crash in Nextcloud TablesAnalysed#3508852ValidInput Validation and LogicLow2026-10-20–25
Unrestricted file upload on the image of contactsAnalysed#808287ValidInput Validation and LogicLow2020-07-08$10024
User scoped external storage can be used to gather credentials of other usersAnalysed#1978882ValidInput Validation and LogicHigh2023-06-27–23
Calendar attachments of local files are offered to downloadedAnalysed#3112033ValidInput Validation and LogicMedium2025-12-05–22
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
Missing Duplicate Check allowing Multiple Retention Rules per System TagAnalysed#3521646ValidInput Validation and LogicLow2026-09-05–20
When sharing a Deck card in conversation the metaData can be manipulated to open arbitrary URL#1358977ValidInput Validation and LogicMedium2022-02-15–19
No rate limiting on sinup page#922470ValidInput Validation and LogicLow2020-09-28–16
bypass forced password protection via circles app#1406926ValidInput Validation and LogicLow2022-06-19$10014
Federated share accepting/declining is not logged in audit log#1200815ValidInput Validation and LogicLow2022-09-03–12
objectId in share location can be set to open arbitrary URL or Deeplinks#1337178ValidInput Validation and LogicMedium2022-03-08–8
Name collision of shared folders#1697281ValidInput Validation and LogicMedium2023-04-29–5

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 (4,365 analysed so far), which can be wrong. Data as of 2026-11-15.