CVE-2024-32874: Malicious Long Unicode filenames may cause a Multiple Application-level Denial of Service

Should you act?

Normal patch cycle

No exploitation signal; fix it in your next routine update if you are affected. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
• EPSS 0.8%, percentile 55: FIRST’s model estimates a 0.8% chance of exploitation activity in the next 30 days, higher than 55% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
• Needs an account (high (admin)). Exposure depends on who can log in.
• Only applies if your dependency tree includes frigate (PyPI) < 0.13.2, fixed in 0.13.2. Check your lockfile, including transitive dependencies.

What it is

Frigate is a network video recorder (NVR) with realtime local object detection for IP cameras. Below 0.13.2 Release, when uploading a file or retrieving the filename, a user may intentionally use a large Unicode filename which would lead to a application-level denial of service. This is due to no limitation set on the length of the filename and the costy use of the Unicode normalization with the form NFKD under the hood of securefilename().

From the GitHub advisory

Important: Exploiting this vulnerability requires the attacker to have access to your Frigate instance, which means they could also just delete all of your recordings or perform any other action. If you have configured authentication in front of Frigate via a reverse proxy, then this vulnerability is not exploitable without first getting around your authentication method. For many obvious reasons in addition to this one, please don't expose your Frigate instance publicly without any kind of authentication.

Summary

When uploading a file or retrieving the filename, a user may intentionally use a large Unicode filename which would lead to a application-level denial of service. This is due to no limitation set on the length of the filename and the costy use of the Unicode normalization with the form NFKD under the hood of securefilename().

I idenfied multiple vulnerable paths on blakeblackshear/frigate repository. In all of those paths, it was possible for a malicious user to send a filename equals to the output of : python3 -c "print('℀' 1000000)" which would reach the werkzeug securefilename() call , which in turn under the hood uses a compatibility Unicode normalization with NFKC/NFKD form. In sum, the latter call would be costly in matter of CPU resource and may lead to the application-level denial of service.

Vulnerable Paths

Weakness type: CWE-770.

Product: frigate (PyPI) · Assigned by: GitHub_M · Published: 2024-05-09

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: high (admin)
• User interaction: none
• Scope: changed (can affect other components)

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation none, automatable no, technical impact partial.
• FIRST EPSS (model of 2026-10-21): 0.77% probability of exploitation activity in the next 30 days; percentile 55.

Timeline

• 2024-05-09 — CVE record published by GitHub_M
• 2024-05-09 — GitHub-reviewed advisory GHSA-w4h6-9wrp-v5jq published (critical)
• 2024-08-02 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-w4h6-9wrp-v5jq github.com
2. CVE.org record CVE-2024-32874 cve.org
3. NVD entry CVE-2024-32874 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
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3. github.com github.com
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7. github.com github.com
8. github.com github.com

Critical PyPI advisories · Today’s Security Digest