# CVE-2021-3538: go.uuid has Predictable UUID Identifiers

> Predictable UUID generation in the satori/go.uuid library allows attackers to guess identifiers, potentially bypassing security controls or accessing sensitive data.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 2 Jun 2021
- **Updated:** 3 Aug 2024
- **Also known as:** CLEANSTART-2026-NO94084, GHSA-33m6-q9v5-62r7, GO-2022-0244

## What is CVE-2021-3538?

CVE-2021-3538 is a critical vulnerability in satori/go.uuid, published on 2 Jun 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A flaw was found in github.com/satori/go.uuid in versions from commit 0ef6afb2f6cdd6cdaeee3885a95099c63f18fc8c to d91630c8510268e75203009fe7daf2b8e1d60c45. Due to insecure randomness in the g.rand.Read function the generated UUIDs are predictable for an attacker.

Weakness: CWE-338 (Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG))

## Which versions are affected by CVE-2021-3538?

3 open source packages ship an affected version, including github.com/satori/go.uuid. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/satori/go.uuid` | Go | From 1.2.1-0.20180103161547-0ef6afb2f6cd | 1.2.1-0.20180404165556-75cca531ea76 |
| `github.com/satori/go.uuid` | Go | From 1.2.1-0.20180103161547-0ef6afb2f6cd | 1.2.1-0.20180404165556-75cca531ea76 |
| `github.com/satori/go.uuid` | Go | From 1.2.1-0.20180103161547-0ef6afb2f6cd | 1.2.1-0.20180404165556-75cca531ea76 |

Products: Satori Uuid.

## How do I fix CVE-2021-3538?

Upgrade github.com/satori/go.uuid to 1.2.1-0.20180404165556-75cca531ea76 or later.

## Is CVE-2021-3538 being exploited?

There is no known exploitation of CVE-2021-3538 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-3538 and fix it if it is affected.

What it is: CVE-2021-3538 is a critical vulnerability in satori/go.uuid, published on 2 Jun 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-3538 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/satori/go.uuid (Go): affected from 1.2.1-0.20180103161547-0ef6afb2f6cd; fixed in 1.2.1-0.20180404165556-75cca531ea76
- github.com/satori/go.uuid (Go): affected from 1.2.1-0.20180103161547-0ef6afb2f6cd; fixed in 1.2.1-0.20180404165556-75cca531ea76
- github.com/satori/go.uuid (Go): affected from 1.2.1-0.20180103161547-0ef6afb2f6cd; fixed in 1.2.1-0.20180404165556-75cca531ea76

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-2021-3538/ (Markdown: https://insights.sbomify.com/CVE-2021-3538/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-3538
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-3538
- OSV: https://osv.dev/vulnerability/CVE-2021-3538

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-3538/
Summaries are generated and may contain mistakes; the official description above is the record.