# CVE-2021-29499: Predictable SIF UUID Identifiers

> Predictable UUIDs in SIF container images allow attackers to bypass security controls relying on unique identifiers.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 7 May 2021
- **Updated:** 3 Aug 2024
- **Also known as:** DEBIAN-CVE-2021-29499, GHSA-4gh8-x3vv-phhg, GO-2022-0912, UBUNTU-CVE-2021-29499

## What is CVE-2021-29499?

CVE-2021-29499 is a high-severity vulnerability in sylabs sif, published on 7 May 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

SIF is an open source implementation of the Singularity Container Image Format. The `siftool new` command and func siftool.New() produce predictable UUID identifiers due to insecure randomness in the version of the `github.com/satori/go.uuid` module used as a dependency. A patch is available in version >= v1.2.3 of the module. Users are encouraged to upgrade. As a workaround, users passing CreateInfo struct should ensure the `ID` field is generated using a version of `github.com/satori/go.uuid` that is not vulnerable to this issue.

Weakness: CWE-330 (Use of Insufficiently Random Values)

## Which versions are affected by CVE-2021-29499?

3 open source packages ship an affected version, including github.com/sylabs/sif. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/sylabs/sif` | Go | All versions | 1.2.3 |
| `github.com/sylabs/sif` | Go | All versions | 1.2.3 |
| `github.com/sylabs/sif` | Go | All versions | 1.2.3 |

Products: Sylabs Singularity Image Format.

## How do I fix CVE-2021-29499?

Upgrade github.com/sylabs/sif to 1.2.3 or later.

## Is CVE-2021-29499 being exploited?

There is no known exploitation of CVE-2021-29499 in the wild and no public exploit code.

## Other vulnerabilities in sylabs sif

- [CVE-2022-39237](https://insights.sbomify.com/CVE-2022-39237/): Digital Signature Hash Algorithms Not Validated in sylabs/sif (medium 6.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-29499 and fix it if it is affected.

What it is: CVE-2021-29499 is a high-severity vulnerability in sylabs sif, published on 7 May 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-2021-29499 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/sylabs/sif (Go): affected all versions; fixed in 1.2.3
- github.com/sylabs/sif (Go): affected all versions; fixed in 1.2.3
- github.com/sylabs/sif (Go): affected all versions; fixed in 1.2.3

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-2021-29499/ (Markdown: https://insights.sbomify.com/CVE-2021-29499/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-29499
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-29499
- OSV: https://osv.dev/vulnerability/CVE-2021-29499

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From sbomify Insights: https://insights.sbomify.com/CVE-2021-29499/
Summaries are generated and may contain mistakes; the official description above is the record.