CVE-2020-8264

mediumpriority · attend · 47EPSS 0.670 · 99 %ileEUUS

grimoire priorityP1 · Urgent

Exploitable?

—

no known exploitation

Likely / severe?

67.0% (99th) EPSS

CVSS 4.3 · medium

Is it mine?

3 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · nvd · osv

EPSS · scored 2026-10-27

In actionpack gem >= 6.0.0, a possible XSS vulnerability exists when an application is running in development mode allowing an attacker to send or embed (in another page) a specially crafted URL which can allow the attacker to execute JavaScript in the context of the local application. This vulnerability is in the Actionable Exceptions middleware.

cvss

Technical severity, 0–10. One row per scoring source.

6.1

010

base score 0–10 · higher = more severe · hover a vector to decode

v2.04.3mediumAV:N/AC:M/Au:N/C:N/I:P/A:Nprimary · NVD / NIST USexploitability 8.6 · impact 2.9

v3.16.1mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:Nprimary · NVD / NIST USexploitability 2.8 · impact 2.7

v3.16.1mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:Nsecondary · OSV

v3.16.1mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N/E:Hsecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-79USprimaryCWE-79US

affected products (3)

Products and version ranges known to be affected.

n/a https://github.com/rails/rails≤ 6.0.3.4enisa_euvdEU
rubyonrails rails6.0.0 → 6.0.3.4nvdUScpe:2.3:a:rubyonrails:rails:*:*:*:*:*:*:*:*
RubyGems actionpack6.0.0 → 6.0.3.4osvUSpkg:gem/actionpack

advisories (1)

Vendor and ecosystem advisories describing this.

GHSA-35mm-cc6r-8fjpCross-site scripting in actionpack2021-04-07ghsa · osvUS
In actionpack gem >= 6.0.0, a possible XSS vulnerability exists when an application is running in development mode allowing an attacker to send or embed (in another page) a specially crafted URL which can allow the attacker to execute JavaScript in the context of the local application. This vulnerability is in the Actionable Exceptions middleware. Workarounds ----------- Until such time as the patch can be applied, application developers should disable the Actionable Exceptions middleware in their development environment via a line such as this one in their config/environment/development.rb: `config.middleware.delete ActionDispatch::ActionableExceptions`

also known as (3)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd nvd osv NVD CVE.org MITRE

published 2021-01-06modified 2026-06-17

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+53007 more

references (9)

External citations — patches, advisories, analysis.

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