Vulnerability · Published Apr 22, 2026 · Assigned by GitHub_M
CVE-2026-41146facil.io and downstream iodine ruby gem vulnerable to uncontrolled resource consumption and loop with unreachable exit condition
High 8.7
In plain English
A high-severity uncontrolled resource consumption in facil.io from boazsegev. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 30% of all known vulnerabilities).
Official description
facil.io is a C micro-framework for web applications. Prior to commit 5128747363055201d3ecf0e29bf0a961703c9fa0, `fio_json_parse` can enter an infinite loop when it encounters a nested JSON value starting with `i` or `I`. The process spins in user space and pegs one CPU core at ~100% instead of returning a parse error. Because `iodine` vendors the same parser code, the issue also affects `iodine` when it parses attacker-controlled JSON. The smallest reproducer I found is `[i`. The quoted-value form that originally exposed the issue, `[""i`, reaches the same bug because the parser tolerates missing commas and then treats the trailing `i` as the start of another value. Commit 5128747363055201d3ecf0e29bf0a961703c9fa0 fixes the issue.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| RubyGems | iodine | no fix listed | GHSA-2x79-gwq3-vxxm |
Affected products (as reported)
Weakness: CWE-400, CWE-835 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N