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NVD / CVE Program· CNA hackerone

CVE-2020-8163: The is a code injection vulnerability in versions of Rails prior to 5.0.1 that wouldallow an attacker who controlled the `locals` argument…

HighCVSS 8.8 · v3.1—Proof of concept Fix available

Noroxi assessment

Priority: This week (action score 60/100)

  • A ready-made attack module is public (Nuclei); exploiting it takes no special expertise.
  • Public proof-of-concept code exists (Exploit-DB, GitHub); there is no record of exploitation in the wild.
  • Probability of exploitation in the next 30 days: 82.4% (FIRST EPSS); higher than 99.6% of all records.
  • Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: rails (Debian:12) 2:5.2.0+dfsg-2; rails (Debian:9) 2:4.2.7.1-1+deb9u3; actionview (RubyGems) 4.2.11.3.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Don’t wait for the next maintenance window. Upgrade to rails (Debian:12) 2:5.2.0+dfsg-2; rails (Debian:9) 2:4.2.7.1-1+deb9u3; actionview (RubyGems) 4.2.11.3 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

The is a code injection vulnerability in versions of Rails prior to 5.0.1 that wouldallow an attacker who controlled the `locals` argument of a `render` call to perform a RCE.

Published
Jul 2, 2020
Updated
Jun 16, 2026
EPSS
82.4% · 99th percentile

Report tools

JSON

Action score

60

This week

Don’t wait for the next maintenance window.

CVSS
35 / 40 · 8.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
25 / 30 · 82.4%

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • Proof of concept exists, no weaponized module
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
rubyonrailsrails
debiandebian linux

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • debian debian linux9.0
  • rubyonrails railsbefore 5.0.1

Versions reported by the vendor

Affected version ranges reported by the assigning authority (hackerone). Independent of NVD's CPE analysis and usually ahead of it.

  • n/a https://github.com/rails/rails

    • Fixed in 4.2.11.2affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12railsbefore 2:5.2.0+dfsg-22:5.2.0+dfsg-2
Debian:9railsbefore 2:4.2.7.1-1+deb9u32:4.2.7.1-1+deb9u3
RubyGemsactionviewbefore 4.2.11.34.2.11.3
SUSE:OpenStack Cloud 6-LTSSrubygem-actionview-4_2before 4.2.9-9.9.14.2.9-9.9.1
SUSE:OpenStack Cloud 6-LTSSrubygem-activesupport-4_2before 4.2.9-7.6.14.2.9-7.6.1

Same product

rubyonrails: all records

Other highest-scoring records for the same primary product.

  • CVE-2019-5418There is a File Content Disclosure vulnerability in Action View <5.2.2.1, <5.1.6.2, <5.0.7.2, <4.2.11.1 and v3 where specially crafted…KEV
    90Now
  • CVE-2016-0752Directory traversal vulnerability in Action View in Ruby on Rails before 3.2.22.1, 4.0.x and 4.1.x before 4.1.14.1, 4.2.x before 4.2.5.1…KEV
    89Now
  • CVE-2019-5420A remote code execution vulnerability in development mode Rails <5.2.2.1, <6.0.0.beta3 can allow an attacker to guess the automatically…
    66This week

Published before and after this one in the same product

  • ← EarlierCVE-2020-8165Jun 19, 2020 · A deserialization of untrusted data vulnernerability exists in rails < 5.2.4.3, rails < 6.0.3.1 that can allow an attacker to unmarshal…
    53Plan
  • ← EarlierCVE-2020-8167Jun 19, 2020 · A CSRF vulnerability exists in rails <= 6.0.3 rails-ujs module that could allow attackers to send CSRF tokens to wrong domains.
    26Monitor
  • Later →CVE-2020-8166Jul 2, 2020 · A CSRF forgery vulnerability exists in rails < 5.2.5, rails < 6.0.4 that makes it possible for an attacker to, given a global CSRF token…
    18Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
debian:rails2:5.2.0+dfsg-2 · Debian:12Package registry (OSV)
RubyGems:actionview4.2.11.3Package registry (OSV)
suse:rubygem-actionview-4_24.2.9-9.9.1 · SUSE:OpenStack Cloud 6-LTSSPackage registry (OSV)
suse:rubygem-activesupport-4_24.2.9-7.6.1 · SUSE:OpenStack Cloud 6-LTSSPackage registry (OSV)

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

  • Exploit-DB entry ×1
  • Nuclei detection template ×1
  • Proof-of-concept repository on GitHub ×3

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Exploit-DB entrywebapps2020-07-26
Nuclei detection templateNuclei template CVE-2020-8163 —
Proof-of-concept repository on GitHubstars:602020-06-19
Proof-of-concept repository on GitHubstars:42020-07-18
Proof-of-concept repository on GitHubstars:12022-03-24

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. First PoC-14 d
  2. Published
  3. TodayNov 12, 2026+2324 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-94 · Improper Control of Generation of Code ('Code Injection')

CVSS vector

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

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records