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🛡️ CVE-2026-3337 — aws-lc-fips-sys

🟠 CVSS 8.0 — High ✅ No Known Exploit CWE-208 NVD
8.0
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

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

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. aws-lc-sys and aws-lc-fips-sys contain code from AWS-LC. Applications using aws-lc-sys or aws-lc-fips-sys should upgrade to the most recent releases of aws-lc-sys or aws-lc-fips-sys.

Impacted versions:

  • aws-lc-sys versions: >= 0.14.0, < 0.38.0
  • aws-lc-fips-sys versions: >= v0.13.0, < 0.13.12.

Patches

The patch is included in aws-lc-sys v.0.38.0 and aws-lc-fips-sys v0.13.12.

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-sys or aws-lc-fips-sys should upgrade to the most recent releases of aws-lc-sys or aws-lc-fips-sys.

Resources

If there are any questions or comments about this advisory, contact [AWS/Amazon] Security via the[vulnerability reporting page](https://aws.amazon.com/security/vulnerability-reporting) or directly via email to [[email protected]](mailto:[email protected]). Please do not create a public GitHub issue.

Acknowledgement

AWS-LC would like to thank Joshua Rogers (https://joshua.hu/) for collaborating on this issue through the coordinated vulnerability disclosure process.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is high, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity high, availability none.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: High — the attacker first has to win a race, learn a secret or otherwise prepare the target.
  • Privileges required: None — an unauthenticated stranger can try it.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: None.
  • Integrity impact: High — total loss, or loss the attacker controls.
  • Availability impact: None.

Weakness class

CVE-2026-3337 is classified as CWE-208: Observable Timing Discrepancy. Two separate operations in a product require different amounts of time to complete, in a way that is observable to an actor and reveals security-relevant information about the state of the product, such as whether a particular operation was successful or not.

Affected software

CVE-2026-3337 is recorded against 3 packages.

  • aws-lc-fips-sys
  • aws-lc-sys
  • aws-libcrypto (from 3.0.0 up to 3.2.0)

Timeline and source

Published on 3 March 2026 and last revised on 17 June 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

github.com (Web)
github.com (Web)
nvd.nist.gov (Advisory)
aws.amazon.com (Web)
github.com (Package)
rustsec.org (Web)
rustsec.org (Web)

Other advisories for this package

aws-lc-fips-sys has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-208: Observable Timing Discrepancy) in other software:

Details

Severity HIGH
CVSS Score 8.0
CVSS Vector CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
CWE CWE-208
Public Exploit ✅ No
Source NVD
Published 2026-03-03
Updated 2026-08-20
Modified 2026-06-17
Fix URL N/A

Affected Packages

Software From version Fixed in
aws-lc-fips-sys — —
aws-lc-sys — —
aws-libcrypto 3.0.0 3.2.0

Similar Threats

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