How severe is CVE-2024-21520?

No CVSS score has been assigned to CVE-2024-21520 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2024-21520?

CVE-2024-21520 affects the following packages: djangorestframework (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2024-21520?

Update djangorestframework to 3.15.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-21520 is resolved across your whole dependency graph.

How do I detect CVE-2024-21520 in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for djangorestframework, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2024-21520 if there is no patch (or I can't update yet)?

Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Is CVE-2024-21520 actively exploited in the wild?

No public exploit code has been indexed for CVE-2024-21520 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2024-21520?

CVE-2024-21520 has an EPSS (Exploit Prediction Scoring System) score of 1.1%, placing it in the 67th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2024-21520?

CVE-2024-21520 is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2024-21520 published, and has it been updated?

CVE-2024-21520 was published on June 26, 2024 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍 PyPI

Not in CISA KEV

CVE-2024-21520 — djangorestframework

Fix: encode/django-rest-framework@3b41f01

CVE-2024-21520 is a Cross-site Scripting (XSS) vulnerability in djangorestframework. A fix is available for djangorestframework — see the affected versions and patch details below.

Cross-site Scripting in djangorestframework

Also known asGHSA-gw84-84pc-xp82PYSEC-2026-1304

Published

Jun 26, 2024

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

Proof-of-concept exploit code exists

CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.

Exploitation and automatability from CISA’s SSVC triage for CVE-2024-21520.

EPSS Exploitation Probability

via FIRST.org ↗

1.1%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs67th percentile — riskier than 67% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

🐍djangorestframework

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

Versions of the package djangorestframework before 3.15.2 are vulnerable to Cross-site Scripting (XSS) via the break_long_headers template filter due to improper input sanitization before splitting and joining with <br> tags.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`djangorestframework`	all versions	3.15.2`pip install --upgrade 'djangorestframework==3.15.2'`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for djangorestframework, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update djangorestframework to 3.15.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-21520 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatModerate

Product	Fixed in	Advisory
Red Hat Ansible Automation Platform 2.4 for RHEL 8	`automation-controller-0:4.5.12-1.el8ap`	RHSA-2024:7312

Frequently Asked Questions

O3 Security · Impact-Aware SCA

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