Quantum Secular Labs / Blog / Advisories

CVE-2026-119757: BTCPay Server: Authentication bypass

CVE-2026-119757 is rated critical with a CVSS v3.1 base score of 9.8. Per its scoring, it can be exploited over the network, without authentication, without any user interaction. The scored impact on confidentiality, integrity and availability is the highest available.

Vulnerability description

BTCPay Server before 2.4.2, including 2.4.2 release candidates, contains an information disclosure vulnerability that allows unauthenticated remote attackers to retrieve .macaroon credential files for an LND (Lightning Network Daemon) node. Attackers can use the exposed macaroon to gain full control of the LND node, including moving funds, resulting in theft of funds from affected deployments.

Severity breakdown

CVSS v3.1 9.8: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

  • Attack vector: Network. Exploitable remotely over the network, with no need for local or physical access.
  • Attack complexity: Low. No special conditions; the attack can be repeated reliably.
  • Privileges required: None. No account or prior access is needed.
  • User interaction: None. No action from any user is needed.
  • Scope: Unchanged. Impact stays within the vulnerable component.
  • Confidentiality impact: High. Total loss of confidentiality; sensitive data can be fully disclosed.
  • Integrity impact: High. Total loss of integrity; data or system state can be fully modified.
  • Availability impact: High. Total loss of availability; the component can be shut down.

Underlying weakness

CWE-522: Insufficiently Protected Credentials

The product transmits or stores authentication credentials, but it uses an insecure method that is susceptible to unauthorized interception and/or retrieval.

CWE-552: Files or Directories Accessible to External Parties

The product makes files or directories accessible to unauthorized actors, even though they should not be.

Affected products

    References