5.6

CVE-2020-8911: CBC padding oracle in AWS S3 Crypto SDK for GoLang

Modified
AliasesCGA-23mq-84cr-wp7pCGA-254g-fgh9-w8cjCGA-268p-vg9r-xgjx
Published 11-08-2020Last modified 04-08-2024

Vulnerability summary

CVE-2020-8911 is a medium (CVSS 5.6) vulnerability in amazon aws_s3_crypto_sdk. EPSS estimates a 0.35% chance of exploitation in the next 30 days, higher than 28.2% of scored vulnerabilities. 1 public exploit is recorded.

Priority
Routine

Not severe (CVSS 5.6, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
5.6/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.35%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits1github

Advisory lineage

Upstream 0 · Downstream 1 · Related 4
OPENSUSE-SU-2024:14513-1CGA-5P79-WXP7-9267CGA-WJR9-45CJ-3VR5CGA-WP54-C6Q6-Q47J

Timeline

  1. 11-08-2020
    PublishedVulnerability first disclosed.
  2. 04-08-2024
    Last modifiedVulnerability information updated.

Description

A padding oracle vulnerability exists in the AWS S3 Crypto SDK for GoLang versions prior to V2. The SDK allows users to encrypt files with AES-CBC without computing a Message Authentication Code (MAC), which then allows an attacker who has write access to the target's S3 bucket and can observe whether or not an endpoint with access to the key can decrypt a file, they can reconstruct the plaintext with (on average) 128*length (plaintext) queries to the endpoint, by exploiting CBC's ability to manipulate the bytes of the next block and PKCS5 padding errors. It is recommended to update your SDK to V2 or later, and re-encrypt your files.

CVSS metrics

6 scores · 5 sources · 2 versions

EPSS trend

Probability

0.35%

Chance of exploitation in the next 30 days

Percentile

28%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.35% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

1 found
  • githubUnverified

    Security Research

    Maturity: poc

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Chainguard199 products
  • amazon-cloudwatch-agentAll versions (No fix recorded)
  • amazon-cloudwatch-agent-fipsAll versions (No fix recorded)
  • amazon-ecs-agentAll versions (No fix recorded)
  • amazon-ecs-agent-fipsAll versions (No fix recorded)
  • apply-cve-bumpAll versions (No fix recorded)
Amazon1 product

2 vendors · 200 products · Showing 200 of 634

References

10 links