# CVE-2021-29510: Use of "infinity" as an input to datetime and date fields causes infinite loop in pydantic

> Attackers can cause infinite loops and high CPU usage in applications using Pydantic by passing infinity values to date fields.

- **Severity:** Low 3.3 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 13 May 2021
- **Updated:** 3 Aug 2024
- **Also known as:** DEBIAN-CVE-2021-29510, GHSA-5jqp-qgf6-3pvh, PYSEC-2021-47, UBUNTU-CVE-2021-29510, USN-6553-1, openSUSE-SU-2024:11254-1

## What is CVE-2021-29510?

CVE-2021-29510 is a low-severity denial of service vulnerability in Fedoraproject Fedora, published on 13 May 2021. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

Pydantic is a data validation and settings management using Python type hinting. In affected versions passing either `'infinity'`, `'inf'` or `float('inf')` (or their negatives) to `datetime` or `date` fields causes validation to run forever with 100% CPU usage (on one CPU). Pydantic has been patched with fixes available in the following versions: v1.8.2, v1.7.4, v1.6.2. All these versions are available on pypi(https://pypi.org/project/pydantic/#history), and will be available on conda-forge(https://anaconda.org/conda-forge/pydantic) soon. See the changelog(https://pydantic-docs.helpmanual.io/) for details. If you absolutely can't upgrade, you can work around this risk using a validator(https://pydantic-docs.helpmanual.io/usage/validators/) to catch these values. This is not an ideal solution (in particular you'll need a slightly different function for datetimes), instead of a hack like this you should upgrade pydantic. If you are not using v1.8.x, v1.7.x or v1.6.x and are unable to upgrade to a fixed version of pydantic, please create an issue at https://github.com/samuelcolvin/pydantic/issues requesting a back-port, and we will endeavour to release a patch for earlier versions of pydantic.

Weakness: CWE-835 (Loop with Unreachable Exit Condition)

## Which versions are affected by CVE-2021-29510?

7 open source packages ship an affected version, including pydantic. It affects 2 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `pydantic` | PyPI | All versions | 1.6.2, 1.7.4, 1.8.2 |
| `pydantic` | PyPI | All versions | 1.6.2 |
| `pydantic` | PyPI | All versions | 1.6.2 |
| `pydantic` | PyPI | From 1.7 | 1.7.4 |
| `pydantic` | PyPI | From 1.7 | 1.7.4 |
| `pydantic` | PyPI | From 1.8 | 1.8.2 |
| `pydantic` | PyPI | From 1.8 | 1.8.2 |

Products: Fedoraproject Fedora, Pydantic Pydantic.

## How do I fix CVE-2021-29510?

Upgrade pydantic to a fixed version for your release line: 1.6.2, 1.7.4 or 1.8.2.

## Is CVE-2021-29510 being exploited?

There is no known exploitation of CVE-2021-29510 in the wild and no public exploit code.

## Other vulnerabilities in Fedoraproject Fedora

- [CVE-2024-4577](https://insights.sbomify.com/CVE-2024-4577/): PHP-CGI OS Command Injection (critical 9.8, exploited in the wild)
- [CVE-2021-39226](https://insights.sbomify.com/CVE-2021-39226/): Grafana Authentication Bypass (critical 9.8, exploited in the wild)
- [CVE-2019-5544](https://insights.sbomify.com/CVE-2019-5544/): VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2024-4947](https://insights.sbomify.com/CVE-2024-4947/): Google Chromium V8 Type Confusion (critical 9.6, exploited in the wild)
- [CVE-2024-4671](https://insights.sbomify.com/CVE-2024-4671/): Google Chromium Visuals Use-After-Free (critical 9.6, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-29510 and fix it if it is affected.

What it is: CVE-2021-29510 is a low-severity denial of service vulnerability in Fedoraproject Fedora, published on 13 May 2021. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2021-29510 in the wild and no public exploit code.

Affected packages and fixed versions:
- pydantic (PyPI): affected all versions; fixed in 1.6.2, 1.7.4, 1.8.2
- pydantic (PyPI): affected all versions; fixed in 1.6.2
- pydantic (PyPI): affected all versions; fixed in 1.6.2
- pydantic (PyPI): affected from 1.7; fixed in 1.7.4
- pydantic (PyPI): affected from 1.7; fixed in 1.7.4
- pydantic (PyPI): affected from 1.8; fixed in 1.8.2
- pydantic (PyPI): affected from 1.8; fixed in 1.8.2

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-2021-29510/ (Markdown: https://insights.sbomify.com/CVE-2021-29510/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-29510
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-29510
- OSV: https://osv.dev/vulnerability/CVE-2021-29510

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-29510/
Summaries are generated and may contain mistakes; the official description above is the record.