How severe is CVE-2024-27306?

CVE-2024-27306 has a CVSS score of 6.1/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2024-27306?

CVE-2024-27306 affects the following packages: aiohttp (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2024-27306?

Update aiohttp to 3.9.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-27306 is resolved across your whole dependency graph.

How do I detect CVE-2024-27306 in my PyPI dependencies?

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

How do I mitigate CVE-2024-27306 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-2024-27306 actively exploited in the wild?

No public exploit code has been indexed for CVE-2024-27306 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-2024-27306?

CVE-2024-27306 has an EPSS (Exploit Prediction Scoring System) score of 0.7%, placing it in the 52th 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-2024-27306?

CVE-2024-27306 is classified as Cross-site Scripting (XSS) (CWE-79), CWE-80 (CWE-80). These weakness types 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-2024-27306 published, and has it been updated?

CVE-2024-27306 was published on April 18, 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

MEDIUM severity

CVE-2024-27306 — aiohttp

MEDIUMFix: aio-libs/aiohttp@2833552

CVE-2024-27306 is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in aiohttp. A fix is available for aiohttp — see the affected versions and patch details below.

aiohttp vulnerable to XSS on index pages for static file handling

Also known asGHSA-7gpw-8wmc-pm8gPYSEC-2026-1102

Published

Apr 18, 2024

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 29, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2024-27306.

EPSS Exploitation Probability

via FIRST.org ↗

0.7%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs52th percentile — riskier than 52% of all scored CVEsHighest risk

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

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected

🐍aiohttp

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

Summary

A XSS vulnerability exists on index pages for static file handling.

Details

When using web.static(..., show_index=True), the resulting index pages do not escape file names.

If users can upload files with arbitrary filenames to the static directory, the server is vulnerable to XSS attacks.

Workaround

We have always recommended using a reverse proxy server (e.g. nginx) for serving static files. Users following the recommendation are unaffected.

Other users can disable show_index if unable to upgrade.

Patch: https://github.com/aio-libs/aiohttp/pull/8319/files

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`aiohttp`	all versions	3.9.4`pip install --upgrade 'aiohttp==3.9.4'`

Affected Products

2 products · 4 configurations

Application

aiohttpaiohttp

< 3.9.4

range

fedorafedoraproject

3 versions

383940

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for aiohttp, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update aiohttp to 3.9.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-27306 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	`python3x-aiohttp-0:3.9.5-1.el8ap`	RHSA-2024:3781
Red Hat Satellite 6.15 for RHEL 8	`python-aiohttp-0:3.9.4-1.el8pc`	RHSA-2024:5662
RHUI 4 for RHEL 8	`python-aiohttp-0:3.9.4-1.el8ui`	RHSA-2025:1335

UbuntuMEDIUM

USN-7642-1Ubuntu

Frequently Asked Questions

### Summary A XSS vulnerability exists on index pages for static file handling. ### Details When using `web.static(..., show_index=True)`, the resulting index pages do not escape file names. If users can upload files with arbitrary filenames to the static directory, the server is vulnerable to XSS attacks. ### Workaround We have always recommended using a reverse proxy server (e.g. nginx) for serving static files. Users following the recommendation are unaffected. Other users can disable `show_index` if unable to upgrade. ----- Patch: https://github.com/aio-libs/aiohttp/pull/8319/file

O3 Security · Impact-Aware SCA

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