CVE-2021-29247
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedBTCPay Server through 1.0.7.0 could allow a remote attacker to obtain sensitive information, caused by failure to set the HTTPOnly flag for a cookie.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceBTCPay Server versions through 1.0.7.0 fail to set the HTTPOnly flag on certain cookies. This allows client-side scripts to access cookie values via JavaScript, potentially exposing sensitive information such as session identifiers if Cross-Site Scripting (XSS) vulnerabilities exist.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data<= 1.0.7.0CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Check BTCPay Server versionAccess the server's About page (usually /Server/About) or check the Docker image tag / deployed package versionAffected if Version is 1.0.7.0 or lower (any version through 1.0.7.0)
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Identify sensitive cookiesLog into BTCPay Server and open browser Developer Tools (F12). Go to Application tab > Cookies. Look for session cookies, authentication tokens, or cookies with names suggesting user identityAffected if Any sensitive cookies (session, auth, identity-related) are present in the browser
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Inspect HTTPOnly flag on cookiesIn browser Developer Tools, examine the cookie details. Check if the 'HttpOnly' column is checked/true for session or authentication cookies. Alternatively, capture HTTP response headers and look for 'Set-Cookie' headersAffected if Sensitive cookies do NOT have the HttpOnly attribute set (Set-Cookie header lacks HttpOnly flag)
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Verify cookie exposure via JavaScriptIn browser console, execute document.cookie to list all accessible cookies. Compare against the cookies seen in Application tabAffected if Sensitive session or authentication cookies appear in document.cookie output, confirming they are accessible to JavaScript
You are affected if running BTCPay Server version 1.0.7.0 or lower AND sensitive cookies (session/auth tokens) are missing the HttpOnly flag, making them accessible to client-side scripts.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataConfigure the application to set the HTTPOnly attribute on all sensitive cookies (particularly session and authentication cookies) to prevent client-side script access.
- Consultation2.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-29247 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-29247 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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