# CVE-2020-8897: Robustness weakness in AWS KMS and Encryption SDKs

> Attackers can craft ciphertexts that decrypt to multiple results due to non-committing AEAD ciphers, impacting data integrity in multi-recipient scenarios.

- **Severity:** Medium 4.8 (`CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 16 Nov 2020
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-wqgp-vphw-hphf, PYSEC-2020-261

## What is CVE-2020-8897?

CVE-2020-8897 is a medium-severity vulnerability in Amazon AWS SDK, published on 16 Nov 2020. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

A weak robustness vulnerability exists in the AWS Encryption SDKs for Java, Python, C and Javalcript prior to versions 2.0.0. Due to the non-committing property of AES-GCM (and other AEAD ciphers such as AES-GCM-SIV or (X)ChaCha20Poly1305) used by the SDKs to encrypt messages, an attacker can craft a unique cyphertext which will decrypt to multiple different results, and becomes especially relevant in a multi-recipient setting. We recommend users update their SDK to 2.0.0 or later.

Weakness: CWE-327 (Use of a Broken or Risky Cryptographic Algorithm), CWE-310

## Which versions are affected by CVE-2020-8897?

5 open source packages ship an affected version, including com.amazonaws:aws-encryption-sdk-java and aws-encryption-sdk. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `com.amazonaws:aws-encryption-sdk-java` | Maven | All versions | 2.0.0 |
| `com.amazonaws:aws-encryption-sdk-java` | Maven | All versions | 2.0.0 |
| `aws-encryption-sdk` | PyPI | All versions | 2.0.0 |
| `aws-encryption-sdk` | PyPI | All versions | 2.0.0 |
| `aws-encryption-sdk` | PyPI | All versions | 2.0.0 |

Products: Amazon Aws Encryption Sdk.

## How do I fix CVE-2020-8897?

Upgrade com.amazonaws:aws-encryption-sdk-java to 2.0.0 or later.

## Is CVE-2020-8897 being exploited?

There is no known exploitation of CVE-2020-8897 in the wild and no public exploit code.

## Other vulnerabilities in Amazon AWS SDK

- [CVE-2024-23680](https://insights.sbomify.com/CVE-2024-23680/): AWS Encryption SDK for Java Improper Verification of Cryptographic Signature (medium 5.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-8897 and fix it if it is affected.

What it is: CVE-2020-8897 is a medium-severity vulnerability in Amazon AWS SDK, published on 16 Nov 2020. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2020-8897 in the wild and no public exploit code.

Affected packages and fixed versions:
- com.amazonaws:aws-encryption-sdk-java (Maven): affected all versions; fixed in 2.0.0
- com.amazonaws:aws-encryption-sdk-java (Maven): affected all versions; fixed in 2.0.0
- aws-encryption-sdk (PyPI): affected all versions; fixed in 2.0.0
- aws-encryption-sdk (PyPI): affected all versions; fixed in 2.0.0
- aws-encryption-sdk (PyPI): affected all versions; fixed in 2.0.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2020-8897/ (Markdown: https://insights.sbomify.com/CVE-2020-8897/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-8897
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-8897
- OSV: https://osv.dev/vulnerability/CVE-2020-8897

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-8897/
Summaries are generated and may contain mistakes; the official description above is the record.