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Fencer Intel
critical 9.8

CVE-2020-8159 in the critical feed json

Arbitrary file write in actionpack-page_caching gem

published 6y ago modified 4mo ago also GHSA-mg5p-95m9-rmfp , EUVD-2020-0432

cvss
9.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
5.4%
EPSS 5.4% chance of exploitation in 30 days, percentile 92%
public exploits
0
none known

Summary

There is a vulnerability in actionpack_page-caching gem < v1.2.1 that allows an attacker to write arbitrary files to a web server, potentially resulting in remote code execution if the attacker can write unescaped ERB to a view.

Patch / fix

  • rubygems actionpack-page_caching 1.2.1
  • rubyonrails actionpack_page-caching 1.2.1
  • ruby-actionpack-page-caching Debian 12 1.2.2-1

debian advisories DEBIAN-CVE-2020-8159

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2020-8159 updated cvss 9.8

rubygem-actionpack-page_caching: allows an attacker to write arbitrary files to a web server, which could result in remote code execution

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

5.38% chance of exploitation in the next 30 days, higher than 92% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P
GitHub 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
rubygems actionpack-page_caching
<1.2.1
1.2.1

Affected products

  • n/a https://github.com/rails/actionpack-page_caching

Classification

Weakness
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory
Technology feeds

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.