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CVE-2026-3337: Timing Side-Channel in AES-CCM Tag Verification in AWS-LC

• Severity: medium (CVSS 5.9 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-03-02 · updated 2026-06-17
• Weakness: CWE-208

Description

Observable timing discrepancy in AES-CCM decryption in AWS-LC allows an unauthenticated user to potentially determine authentication tag validity via timing analysis. The impacted implementations are through the EVP CIPHER API: EVP_aes_128_ccm, EVP_aes_192_ccm, and EVP_aes_256_ccm. Customers of AWS services do not need to take action. Applications using AWS-LC should upgrade to AWS-LC version 1.69.0.

Affected products

• Amazon Aws-Lc-Fips-Sys: from 0.13.0 before 0.13.12 — fixed in 0.13.12
• Amazon Aws-Lc-Sys: from 0.14.0 before 0.38.0 — fixed in 0.38.0
• Amazon Aws Libcrypto: from 1.21.0 before 1.69.0; from 3.0.0 before 3.2.0 — fixed in 1.69.0, 3.2.0

How to fix

Upgrade to a fixed version: Amazon Aws-Lc-Fips-Sys 0.13.12; Amazon Aws-Lc-Sys 0.38.0; Amazon Aws Libcrypto 1.69.0, 3.2.0. Check the vendor advisory for mitigations.

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-frmv-5gcm-jwxh

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