CWE-1322

Use of Blocking Code in Single-threaded, Non-blocking Context

The product uses a non-blocking model that relies on a single threaded process for features such as scalability, but it contains code that can block when it is invoked.

CVE-2026-19484 (GCVE-0-2026-19484)
Vulnerability from cvelistv5
Published
2026-08-13 08:50
Modified
2026-08-13 14:27
Severity ?
7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE
  • CWE-835 - Loop with Unreachable Exit Condition ('Infinite Loop')
  • CWE-1322 - Use of Blocking Code in Single-threaded, Non-blocking Context
Summary
@fastify/busboy is a multipart form-data parser. In versions 3.1.0 through 3.2.0, a remote unauthenticated attacker can stall the Node.js event loop by sending a multipart request whose boundary is crafted to a specific length. The vendored streaming search stores its skip table in a fixed 256 entry byte array, and a boundary of exactly 252 bytes makes the search needle 256 bytes, which truncates the default skip distance to zero and turns the search into a CPU bound loop on a small body. A single small request can keep one core busy and deny service to other requests handled by the same process. The issue is fixed in @fastify/busboy 3.2.1, which widens the skip table so the skip distance is preserved. Users should upgrade to 3.2.1.
References
Impacted products
Vendor Product Version
@fastify/busboy @fastify/busboy Version: 3.1.0   ≤
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CVE-2026-42256 (GCVE-0-2026-42256)
Vulnerability from cvelistv5
Published
2026-05-09 19:38
Modified
2026-05-11 17:04
Severity ?
6.0 (Medium) - CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CWE
  • CWE-1322 - Use of Blocking Code in Single-threaded, Non-blocking Context
  • CWE-770 - Allocation of Resources Without Limits or Throttling
Summary
Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. From versions 0.4.0 to before 0.4.24, 0.5.0 to before 0.5.14, and 0.6.0 to before 0.6.4, when authenticating a connection with SCRAM-SHA1 or SCRAM-SHA256, a hostile server can perform a computational denial-of-service attack on the client process by sending a big iteration count value. This issue has been patched in versions 0.4.24, 0.5.14, and 0.6.4.
References
Impacted products
Vendor Product Version
ruby net-imap Version: >= 0.4.0, < 0.4.24
Version: >= 0.5.0, < 0.5.14
Version: >= 0.6.0, < 0.6.4
 Create a notification for this product.
Show details on NVD website

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CVE-2026-71439 (GCVE-0-2026-71439)
Vulnerability from cvelistv5
Published
2026-08-06 20:01
Modified
2026-08-07 17:09
Severity ?
5.3 (Medium) - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:L
CWE
  • CWE-606 - Unchecked Input for Loop Condition
  • CWE-1322 - Use of Blocking Code in Single-threaded, Non-blocking Context
Summary
Mermaid is a JavaScript tool that uses Markdown-inspired text to create and modify diagrams and charts. From version 11.6.0 until 11.16.1, Mermaid Radar Diagrams allow arbitrary large values for the ticks parameter, which can cause high CPU usage and freeze the rendering webpage or JavaScript process for long periods of time, potentially until the process is killed from memory exhaustion. This issue is fixed in version 11.16.1.
References
Impacted products
Vendor Product Version
mermaid-js mermaid Version: >= 11.6.0, < 11.16.1
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Mitigation

Phase: Implementation

Description:

  • Generally speaking, blocking calls should be replaced with non-blocking alternatives that can be used asynchronously. Expensive computations should be passed off to worker threads, although the correct approach depends on the framework being used.
Mitigation

Phase: Implementation

Description:

  • For expensive computations, consider breaking them up into multiple smaller computations. Refer to the documentation of the framework being used for guidance.
CAPEC-25: Forced Deadlock

The adversary triggers and exploits a deadlock condition in the target software to cause a denial of service. A deadlock can occur when two or more competing actions are waiting for each other to finish, and thus neither ever does. Deadlock conditions can be difficult to detect.

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