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CVE-2020-9309

HIGHCVSS 8.8/10EPSS 1.84%

Last modified

CVE-2020-9309 is a high-severity vulnerability rated 8.8/10 on the CVSS scale. Silverstripe CMS through 4.5 can be susceptible to script execution from malicious upload contents under allowed file extensions (for example HTML code in a TXT file). When these files are stored as protected or draft files, the MIME detection can cause browsers to execute the file contents. EPSS estimates a 1.84% chance of exploitation in the next 30 days.

Description

Silverstripe CMS through 4.5 can be susceptible to script execution from malicious upload contents under allowed file extensions (for example HTML code in a TXT file). When these files are stored as protected or draft files, the MIME detection can cause browsers to execute the file contents. Uploads stored as protected or draft files are allowed by default for authorised users only, but can also be enabled through custom logic as well as modules such as silverstripe/userforms. Sites using the previously optional silverstripe/mimevalidator module can configure MIME whitelists rather than extension whitelists, and hence prevent this issue. Sites on the Common Web Platform (CWP) use this module by default, and are not affected.

Metrics

CVSS 3.1
8.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS Probability
1.84%

76.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
SilverstripeMimevalidator< 2.0.0
SilverstripeRecipe>= 4.0.0, < 4.6.0

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2020-9309?
Silverstripe CMS through 4.5 can be susceptible to script execution from malicious upload contents under allowed file extensions (for example HTML code in a TXT file). When these files are stored as protected or draft files, the MIME detection can cause browsers to execute the file contents. Uploads stored as protected or draft files are allowed by default for authorised users only, but can also be enabled through custom logic as well as modules such as silverstripe/userforms. Sites using the previously optional silverstripe/mimevalidator module can configure MIME whitelists rather than extension whitelists, and hence prevent this issue. Sites on the Common Web Platform (CWP) use this module by default, and are not affected.
How severe is CVE-2020-9309?
CVE-2020-9309 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 1.84% probability of exploitation in the next 30 days.
How do I fix CVE-2020-9309?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-9309?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST