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Fencer Vulns
high 7.5

CVE-2020-8162 json

Circumvention of file size limits in ActiveStorage

published 2020-05-26 6 y ago modified 2026-06-17 4 mo ago also GHSA-m42x-37p3-fv5w , EUVD-2020-0430

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
3.0%
EPSS 3.0% chance of exploitation in 30 days, percentile 87%
public exploits
0
none known

Summary

A client side enforcement of server side security vulnerability exists in rails < 5.2.4.2 and rails < 6.0.3.1 ActiveStorage's S3 adapter that allows the Content-Length of a direct file upload to be modified by an end user bypassing upload limits.

Patch / fix

  • rubygems activestorage 5.2.4.3, 6.0.3.1
  • rubyonrails rails 5.2.4.2, 6.0.3.1
  • rails Debian 14, Debian 13, Debian 12 2:5.2.4.3+dfsg-1

debian advisories DEBIAN-CVE-2020-8162

  • tfm satellite capsule 6.9, satellite 6.9 6.1-4.el7sat
  • kobo satellite capsule 6.9, satellite 6.9 0.5.1-1.el7sat
  • pulp satellite capsule 6.9, satellite 6.9 2.21.5-2.el7sat
  • gofer satellite capsule 6.9, satellite 6.9 2.12.5-7.el7sat
  • future satellite capsule 6.9, satellite 6.9 0.16.0-11.el7sat
  • ostree satellite capsule 6.9, satellite 6.9 2017.1-2.atomic.el7
  • foreman satellite capsule 6.9, satellite 6.9 2.3.1.20-1.el7sat
  • katello satellite capsule 6.9, satellite 6.9 3.18.1-3.el7sat

red hat advisories RHSA-2021:1313

  • rubygem-activestorage-6.0 openSUSE Tumbleweed 6.0.4.4-1.1

opensuse advisories openSUSE-SU-2024:11827-1

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-2020-8162 updated cvss 0.0

rubygem-activestorage: circumvention of file size limits in ActiveStorage

  • Red Hat CloudForms Management Engine 5 cfme-gemset
    affected: no fix planned “Will not fix”
  • Red Hat Satellite 6.9 tfm 6.1-4.el7sat, kobo 0.5.1-1.el7sat, pulp 2.21.5-2.el7sat, gofer 2.12.5-7.el7sat, libsolv 0.7.12-2.el7pc, receptor 0.6.3-1.el7ar, +639 more Red Hat Satellite Capsule 6.9 tfm 6.1-4.el7sat, kobo 0.5.1-1.el7sat, pulp 2.21.5-2.el7sat, gofer 2.12.5-7.el7sat, libsolv 0.7.12-2.el7pc, future 0.16.0-11.el7sat, +238 more
    fixed: vendor fix RHSA-2021:1313

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

3.03% chance of exploitation in the next 30 days, higher than 87% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • hackerone.com https://hackerone.com/reports/789579 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:P/A:N
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Affected packages

ecosystem package affected fixed in
rubygems activestorage
>=5.0.0, <5.2.4.3
>=6.0.0, <6.0.3.1
5.2.4.3
6.0.3.1

Affected products

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

Classification

Weakness
  • CWE-602 Client-Side Enforcement of Server-Side Security
  • CWE-434 Unrestricted Upload of File with Dangerous Type
Technology feeds

References

Sources

Fencer Vulns 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.