CVE-2020-8912

Name: CVE-2020-8912
Creator: NVD / NIST
Published: 2020-08-11T20:15:13.323+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

LOWCVSS 2.5/10EPSS 0.23%

Last modified Jun 17, 2026

CVE-2020-8912 is a low-severity vulnerability rated 2.5/10 on the CVSS scale. A vulnerability in the in-band key negotiation exists in the AWS S3 Crypto SDK for GoLang versions prior to V2. An attacker with write access to the targeted bucket can change the encryption algorithm of an object in the bucket, which can then allow them to change AES-GCM to AES-CTR. EPSS estimates a 0.23% chance of exploitation in the next 30 days.

Description

A vulnerability in the in-band key negotiation exists in the AWS S3 Crypto SDK for GoLang versions prior to V2. An attacker with write access to the targeted bucket can change the encryption algorithm of an object in the bucket, which can then allow them to change AES-GCM to AES-CTR. Using this in combination with a decryption oracle can reveal the authentication key used by AES-GCM as decrypting the GMAC tag leaves the authentication key recoverable as an algebraic equation. It is recommended to update your SDK to V2 or later, and re-encrypt your files.

Metrics

CVSS 3.1

2.5/10

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N

EPSS Probability

0.23%

13.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Amazon	Aws S3 Crypto Sdk	< 2.0

References

https://aws.amazon.com/blogs/developer/updates-to-the-amazon-s3-encryption-client/?s=09Vendor Advisory
https://github.com/google/security-research/security/advisories/GHSA-7f33-f4f5-xwgwExploit, Third Party Advisory
https://aws.amazon.com/blogs/developer/updates-to-the-amazon-s3-encryption-client/?s=09Vendor Advisory
https://github.com/google/security-research/security/advisories/GHSA-7f33-f4f5-xwgwExploit, Third Party Advisory

Timeline

Published: Aug 11, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-8912?

How severe is CVE-2020-8912?

CVE-2020-8912 has a CVSS score of 2.5/10 (LOW severity). The EPSS model estimates a 0.23% probability of exploitation in the next 30 days.

How do I fix CVE-2020-8912?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-8912?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST