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CVE-2026-104891NVD status: Deferred

mppx-condition-gate: Authentication Bypass by Spoofing

CVE-2026-104891 is a high-severity authentication bypass by spoofing vulnerability in mppx-condition-gate from Douglasborthwick-crypto, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected mppx-condition-gate versions: < b1d9935a57ba6d32da49eead1bfb459ad0cd55ab. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.28% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Check which version of mppx-condition-gate you run against the affected versions below, and install the vendor's latest release.
  2. Read the advisory on github.com for workarounds and exact fixed builds.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
Douglasborthwick-cryptomppx-condition-gate< b1d9935a57ba6d32da49eead1bfb459ad0cd55abNot stated
@insumermodelmppx-condition-gate< 3.0.0Not stated
@insumermodelmppx-token-gate< 1.0.4Not stated

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
NoneNothing can be modified.
Availability
NoneAvailability is not affected.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N. Scored by CNA (github.com).

Official description

mppx-condition-gate provides conditional free-access wrappers for mppx payment methods. Prior to @insumermodel/mppx-condition-gate 3.0.0 and @insumermodel/mppx-token-gate 1.0.4, the packages read a wallet address from the client-supplied credential.source, checked whether that public address met configured on-chain conditions, and returned a successful free-access receipt without invoking the wrapped payment verifier or proving that the caller controlled the wallet. An unauthenticated attacker could name any qualifying wallet and obtain content that should require payment, and cached grants could be reused for the configured cache lifetime. The corrected packages prevent free-access authorization unless payer control has been established. These issues are fixed in @insumermodel/mppx-condition-gate 3.0.0 and @insumermodel/mppx-token-gate 1.0.4.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Authentication Bypass by Spoofing

This attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks.

More Authentication Bypass by Spoofing vulnerabilities (CWE-290)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Authentication Bypass by Spoofing vulnerabilities

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