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Findings

CVE-2026-41146

facil.io is a C micro-framework for web applications.

Published Apr 22, 2026 · updated Jun 17, 2026

facil.io is a C micro-framework for web applications. Prior to commit 5128747363055201d3ecf0e29bf0a961703c9fa0, can enter an infinite loop when it encounters a nested JSON value starting with or . The process spins in user space and pegs one CPU core at ~100% instead of returning a parse error. Because vendors the same parser code, the issue also affects when it parses attacker-controlled JSON. The smallest reproducer I found is . The quoted-value form that originally exposed the issue, , reaches the same bug because the parser tolerates missing commas and then treats the trailing as the start of another value. Commit 5128747363055201d3ecf0e29bf0a961703c9fa0 fixes the issue.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Apr 22, 2026 · NIST NVD

    Detected

    facil.io is a C micro-framework for web applications. Prior to commit 5128747363055201d3ecf0e29bf0a961703c9fa0, can enter an infinite loop when it encounters a nested JSON value starting with or . The process spins in user space and pegs one CPU core at ~100% instead of returning a parse error. Because vendors the same parser code, the issue also affects when it parses attacker-controlled JSON. Th

  2. Jun 17, 2026 · NIST NVD

    Updated

    facil.io is a C micro-framework for web applications. Prior to commit 5128747363055201d3ecf0e29bf0a961703c9fa0, can enter an infinite loop when it encounters a nested JSON value starting with or . The process spins in user space and pegs one CPU core at ~100% instead of returning a parse error. Because vendors the same parser code, the issue also affects when it parses attacker-controlled JSON. Th

Sources

  • CVE.orgVulnerability recordCVE-2026-41146

    Official CVE identifier

    cve.org
  • NIST NVDVulnerability recordCVE-2026-41146

    facil.io is a C micro-framework for web applications. Prior to commit 5128747363055201d3ecf0e29bf0a961703c9fa0, can enter an infinite loop when it encounters a nested JSON value starting with or . The process spins in user space and pegs one CPU core at ~1

    nvd.nist.gov

References