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Timing Side-Channel in AES-CCM Tag Verification in AWS-LC

Moderate
torben-hansen published GHSA-frmv-5gcm-jwxh Mar 2, 2026

Package

AWS-LC

Affected versions

>= v1.21.0, < v1.69.0
>= AWS-LC-FIPS-3.0.0, < AWS-LC-FIPS-3.2.0

Patched versions

v1.69.0
AWS-LC-FIPS-3.2.0

Description

Summary

AWS-LC is an open-source, general-purpose cryptographic library.

Impact

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 the most recent release of AWS-LC.

Impacted versions

From v1.21.0 through v1.68.0.
From AWS-LC-FIPS-3.0.0 through AWS-LC-FIPS-3.1.0.

Patches

The patch is included in v1.69.0 and AWS-LC-FIPS-3.2.0.

Workarounds

In the special cases of using AES-CCM with (M=4, L=2), (M=8, L=2), or (M=16, L=2), applications can workaround this issue by using AES-CCM through the EVP AEAD API using implementations EVP_aead_aes_128_ccm_bluetooth, EVP_aead_aes_128_ccm_bluetooth_8, and, EVP_aead_aes_128_ccm_matter respectively.

Otherwise, there is no workaround and applications using AWS-LC should upgrade to the most recent releases of AWS-LC.

References

If you have any questions or comments about this advisory, we ask that you contact AWS Security via our vulnerability reporting page or directly via email to aws-security@amazon.com. Please do not create a public GitHub issue.

Acknowledgement

We would like to thank Joshua Rogers (https://joshua.hu/) of AISLE Research Team (https://aisle.com) for collaborating on this issue through the coordinated vulnerability disclosure process.

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

CVE ID

CVE-2026-3337

Weaknesses

No CWEs