VulnerabilityAnalyzed

CVE-2026-3337

Observable timing discrepancy in AES-CCM decryption in AWS-LC allows an unauthenticated user to potentially determine authentication tag validity via timing analysis.

HIGH 8.2EPSS 1.08%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (1.08%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

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.

CVSS 4.0: 8.2 HIGHCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
EPSS: 1.08% probability · 63th percentile
CISA KEV: Not listed
Weakness: CWE-208
Affected: amazon/aws-lc-fips-sys · amazon/aws-lc-sys · amazon/aws libcrypto
Source: ff89ba41-3aa1-4d27-914a-91399e9639e5

References

https://aws.amazon.com/security/security-bulletins/2026-005-AWS/Vendor Advisory
https://github.com/aws/aws-lc/releases/tag/v1.69.0Release Notes
https://github.com/aws/aws-lc/security/advisories/GHSA-frmv-5gcm-jwxhVendor Advisory

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.