PatchSiren cyber security CVE debrief

CVE-2026-3336 AWS CVE debrief

CVE-2026-3336 is a HIGH-severity vulnerability in AWS-LC, a cryptographic library developed by Amazon. The vulnerability is caused by improper certificate validation in the PKCS7_verify() function, which allows an unauthenticated attacker to bypass certificate chain verification when processing PKCS7 objects with multiple signers. However, customers of AWS services do not need to take action. Applications using AWS-LC should upgrade to AWS-LC version 1.69.0 to mitigate this vulnerability. The Common Vulnerability Scoring System (CVSS) score for this vulnerability is 8.7, indicating a high level of severity. The vulnerability was published on March 2, 2026, and last modified on June 30, 2026.

Vendor: AWS
Product: AWS-LC
CVSS: HIGH 8.7
CISA KEV: Not listed in stored evidence
Original CVE published: 2026-03-02
Original CVE updated: 2026-07-15
Advisory published: 2026-03-02
Advisory updated: 2026-07-15

Who should care

Organizations using AWS-LC in their applications should prioritize upgrading to AWS-LC version 1.69.0 to mitigate this vulnerability. Additionally, security teams and developers responsible for maintaining and updating cryptographic libraries should be aware of this vulnerability and take necessary actions. Red Hat users can refer to errata RHSA-2026:5459 for more information.

Technical summary

The vulnerability is caused by improper certificate validation in the PKCS7_verify() function in AWS-LC. This function is used to verify the certificate chain of a PKCS7 object, which is a type of cryptographic message. The vulnerability allows an unauthenticated attacker to bypass certificate chain verification when processing PKCS7 objects with multiple signers, except the final signer. This could potentially allow an attacker to forge or tamper with cryptographic messages. The vulnerability has a CVSS score of 8.7, indicating a high level of severity. AWS-LC version 1.69.0 fixes this vulnerability.

Defensive priority

Upgrade to AWS-LC version 1.69.0 to mitigate this vulnerability. Review and update cryptographic library dependencies to ensure the latest security patches are applied.

Recommended defensive actions

Upgrade to AWS-LC version 1.69.0
Review and update cryptographic library dependencies
Monitor for any suspicious activity related to PKCS7 objects
Implement additional security measures to detect and prevent potential attacks
Refer to vendor advisories and errata for more information

Evidence notes

The vulnerability was published on March 2, 2026, and last modified on June 30, 2026. The CVSS score for this vulnerability is 8.7, indicating a high level of severity. AWS-LC version 1.69.0 fixes this vulnerability. Customers of AWS services do not need to take action. Red Hat users can refer to errata RHSA-2026:5459 for more information.

Sources and references

Verified primary and authoritative sources

CVE-2026-3336 CVE Program record
Publisher, destination, and source semantics verified

URL: https://www.cve.org/CVERecord?id=CVE-2026-3336

CVE Program - Official CVE Program record with source-provided CVE metadata.
CVE-2026-3336 NVD vulnerability detail
Publisher, destination, and source semantics verified

URL: https://nvd.nist.gov/vuln/detail/CVE-2026-3336

NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Mitigation or vendor reference
Unverified legacy reference

URL: https://aws.amazon.com/security/security-bulletins/2026-005-AWS/

ff89ba41-3aa1-4d27-914a-91399e9639e5 - Vendor Advisory
Mitigation or vendor reference
Unverified legacy reference

URL: https://github.com/aws/aws-lc/releases/tag/v1.69.0

ff89ba41-3aa1-4d27-914a-91399e9639e5 - Release Notes
Mitigation or vendor reference
Unverified legacy reference

URL: https://github.com/aws/aws-lc/security/advisories/GHSA-cfwj-9wp5-wqvp

ff89ba41-3aa1-4d27-914a-91399e9639e5 - Vendor Advisory
Source reference
Unverified legacy reference

URL: https://access.redhat.com/errata/RHSA-2026:5459

0b0ca135-0b70-47e7-9f44-1890c2a1c46c
Source reference
Unverified legacy reference

URL: https://access.redhat.com/security/cve/CVE-2026-3336

0b0ca135-0b70-47e7-9f44-1890c2a1c46c
Source reference
Unverified legacy reference

URL: https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-3336.json

0b0ca135-0b70-47e7-9f44-1890c2a1c46c

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.