Biscuit AuthApplication · Biscuitsec
CVE-2024-41949
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 · uneditedbiscuit-rust is the Rust implementation of Biscuit, an authentication and authorization token for microservices architectures. Third-party blocks can be generated without transferring the whole token to the third-party authority. Instead, a ThirdPartyBlock request can be sent, providing only the necessary info to generate a third-party block and to sign it, which includes the public key of the previous block (used in the signature) and the public keys part of the token symbol table (for public key interning in datalog expressions). A third-part block request forged by a malicious user can trick the third-party authority into generating datalog trusting the wrong keypair.
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 confidenceThe vulnerability allows a malicious user to forge a ThirdPartyBlock request with incorrect public keys, tricking the third-party authority into generating a datalog block that trusts the wrong keypair. This public key substitution during third-party block generation enables token manipulation by an attacker.
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
Biscuit AuthApplication
< 5.0.0CVSS 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
- Low
- User interaction
- None
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/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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Identify Biscuit Auth library versionCheck your project's dependency manifest (package.json, Cargo.toml, Gemfile, pom.xml, requirements.txt, or similar) for the biscuit or biscuit-auth package versionAffected if The installed version is lower than 5.0.0
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Locate ThirdPartyBlock generation codeSearch your codebase for references to ThirdPartyBlock, third_party_block, or thirdparty_block in your source files and configurationAffected if Your application contains code that generates ThirdPartyBlocks for token handling
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Identify third-party block request handlersSearch for endpoints, functions, or APIs that accept ThirdPartyBlock requests, particularly those that process public keys from external requestsAffected if Your system exposes functionality that accepts third-party block requests from users or external services
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Check public key validation in third-party block flowReview the code handling ThirdPartyBlock generation to determine if incoming public keys are validated against expected token public keys before block creationAffected if No validation or insufficient validation of public keys occurs before generating third-party blocks
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Verify token issuance uses vulnerable code pathTrace the token issuance flow to confirm that third-party block generation with user-supplied public keys is actually executed at runtimeAffected if Tokens are issued through a flow that involves generating third-party blocks with potentially untrusted public keys
Your environment is affected if you run any version of Biscuitsec Biscuit Auth below 5.0.0 and your application generates ThirdPartyBlocks using public keys from untrusted sources without validating them against expected token keys.
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.
dbcve · scoped5.0.0
Implement validation of public keys in ThirdPartyBlock requests to ensure they match the expected token public keys before generating any third-party blocks; consider requiring authenticated requests for third-party block generation.
biscuit-rust version 5.0.0 or later
- Update the biscuit-rust dependency in your project's Cargo.toml file to version 5.0.0 or later
- Run cargo update to fetch the new dependency version
- Run cargo build to recompile your project with the fixed version
- Verify the build completes successfully
- Run your test suite to ensure no regressions
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Biscuit Auth
Scoped from the published advisory
- Consultation2.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,480.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2024-41949 — 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-2024-41949 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
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