Summary
mppx-condition-gate: Free-access path grants on a self-declared wallet without proving control
Affected versions
Every published version of both packages is affected. The vulnerable control flow is present from the first release of each.
Workarounds
Remove the condition gate from the payment method until a fixed version is installed, so all requests take the normal paid path. Alternatively, ensure the wrapped payment method has already bound the credential to the payer before the gate is consulted.
Credit
Reported by @chenshj73, who identified the issue, traced the exact code path, and proposed correct remediations.
Impact
Both packages wrap an mppx payment method so that a wallet meeting on-chain conditions is granted free access instead of being charged.
The free-access path reads the payer address from credential.source, a client-supplied DID in the payment credential, asks InsumerAPI whether that address satisfies the configured conditions, and on a pass returns a successful receipt without ever calling the wrapped payment verifier. Nothing in that path establishes that the caller controls the wallet it named.
Because qualifying wallets are public chain state, an attacker does not need to guess one. Naming any qualifying address in credential.source is sufficient to obtain free access to a route that should have been paid for. An in-process cache (default TTL 300s, keyed on wallet and conditions) then re-serves the grant without re-evaluating.
mppx documents this requirement explicitly. Its type definitions describe source as "an asserted identity, not independent proof of control", and state that methods relying on it "must validate the relationship to the credential payload". These packages did not.
This is a defect in these wrapper packages, not in the attestation they consume. The attestation answers one question, does this wallet satisfy these conditions, and answered it honestly about the address it was given. Binding that address to the caller was the wrapper's responsibility.
The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions. Typical impact: unauthorized data access or execution of privileged operations.
CVE-2026-104891 has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (3.0.0, 1.0.4); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Fixed releases will not grant free access unless the payer has been proven, and fall through to the paid path wherever no proven payer is available.
Frequently Asked Questions
- What is CVE-2026-104891? CVE-2026-104891 is a high-severity incorrect authorization vulnerability in @insumermodel/mppx-condition-gate (npm), affecting versions <= 2.0.3. It is fixed in 3.0.0, 1.0.4. The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions.
- How severe is CVE-2026-104891? CVE-2026-104891 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which packages are affected by CVE-2026-104891?
@insumermodel/mppx-condition-gate(npm) (versions <= 2.0.3)@insumermodel/mppx-token-gate(npm) (versions <= 1.0.3)
- Is there a fix for CVE-2026-104891? Yes. CVE-2026-104891 is fixed in 3.0.0, 1.0.4. Upgrade to this version or later.
- Is CVE-2026-104891 exploitable, and should I be worried? Whether CVE-2026-104891 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-104891 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-104891?
- Upgrade
@insumermodel/mppx-condition-gateto 3.0.0 or later - Upgrade
@insumermodel/mppx-token-gateto 1.0.4 or later
- Upgrade