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Fencer Vulns
high 7.5

CVE-2026-33176 json

Rails Active Support has a possible DoS vulnerability in its number helpers

published 2026-03-23 7 mo ago modified 2026-09-10 59 d ago also EUVD-2026-14630 , GHSA-2j26-frm8-cmj9

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.9%
EPSS 0.9% chance of exploitation in 30 days, percentile 58%
public exploits
0
none known

Summary

Active Support is a toolkit of support libraries and Ruby core extensions extracted from the Rails framework. Prior to versions 8.1.2.1, 8.0.4.1, and 7.2.3.1, Active Support number helpers accept strings containing scientific notation (e.g. `1e10000`), which `BigDecimal` expands into extremely large decimal representations. This can cause excessive memory allocation and CPU consumption when the expanded number is formatted, possibly resulting in a DoS vulnerability. Versions 8.1.2.1, 8.0.4.1, and 7.2.3.1 contain a patch.

Patch / fix

  • rubygems activesupport 7.2.3.1, 8.0.4.1, 8.1.2.1
  • activesupport_project activesupport 7.2.3.1, 8.0.4.1, 8.1.2.1
  • rails activesupport 7.2.3.1, 8.0.4.1, 8.1.2.1
  • rubyonrails activesupport 7.2.3.1, 8.0.4.1, 8.1.2.1
  • rails Debian 12 2:6.1.7.10+dfsg-1~deb12u3
  • rails Debian 13 2:7.2.2.2+dfsg-2~deb13u2
  • rails Debian 14 2:7.2.3.1+dfsg-1

debian advisories DEBIAN-CVE-2026-33176

  • candlepin satellite 6.16 4.4.25-1.el8sat
  • candlepin satellite 6.17, satellite 6.16 4.4.25-1.el9sat
  • python-pillow satellite capsule 6.16, satellite 6.16 12.1.1-1.el8pc
  • python-pillow satellite capsule 6.17, satellite capsule 6.16, satellite 6.17 +1 more 12.1.1-1.el9pc
  • python-markdown satellite capsule 6.16, satellite 6.16 3.8.2-1.el8pc
  • python-markdown satellite capsule 6.17, satellite capsule 6.16, satellite 6.17 +1 more 3.8.2-1.el9pc
  • python-pyOpenSSL satellite capsule 6.16, satellite 6.16 24.1.0-2.el8pc
  • python-pyOpenSSL satellite capsule 6.16, satellite 6.16 24.1.0-2.el9pc

red hat advisories RHSA-2026:14874RHSA-2026:14873RHSA-2026:14835

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-2026-33176 updated cvss 6.5

Rails: Active Support: Active Support: Denial of Service via large scientific notation strings

  • Red Hat Satellite 6 rubygem-activesupport
    affected: workaround, no fix available
  • Red Hat Satellite 6.16 for RHEL 8 rubygem-activesupport 6.1.7.8-2.el8sat Red Hat Satellite 6.16 for RHEL 9 rubygem-activesupport 6.1.7.8-2.el9sat
    fixed: vendor fix RHSA-2026:14874
  • Red Hat Satellite 6.17 for RHEL 9 rubygem-activesupport 7.0.8.7-2.el9sat
    fixed: vendor fix RHSA-2026:14873
  • Red Hat Satellite 6.18 for RHEL 9 rubygem-activesupport 7.0.8.7-2.el9sat
    fixed: vendor fix RHSA-2026:14835
  • Red Hat Satellite 6.16 for RHEL 8 candlepin 4.4.25-1.el8sat, satellite 6.16.8-1.el8sat, foreman 3.12.0.15-1.el8sat, python-pillow 12.1.1-1.el8pc, python-markdown 3.8.2-1.el8pc, satellite-cli 6.16.8-1.el8sat, +26 more Red Hat Satellite 6.16 for RHEL 9 candlepin 4.4.25-1.el9sat, satellite 6.16.8-1.el9sat, foreman 3.12.0.15-1.el9sat, python-pillow 12.1.1-1.el9pc, python-markdown 3.8.2-1.el9pc, satellite-cli 6.16.8-1.el9sat, +26 more Red Hat Satellite 6.17 for RHEL 9 candlepin 4.4.25-1.el9sat, satellite 6.17.8-1.el9sat, foreman 3.14.0.16-1.el9sat, python-pillow 12.1.1-1.el9pc, python-markdown 3.8.2-1.el9pc, satellite-cli 6.17.8-1.el9sat, +27 more Red Hat Satellite 6.18 for RHEL 9 candlepin 4.6.5-1.el9sat, satellite 6.18.5-1.el9sat, foreman 3.16.0.16-1.el9sat, python3.12-cffi 2.0.0-1.el9pc, satellite-cli 6.18.5-1.el9sat, foreman-cli 3.16.0.16-1.el9sat, +27 more
    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

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
7 mo ago

Exploit prediction

0.86% chance of exploitation in the next 30 days, higher than 58% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 6.6 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U
CNA 4.0 6.6 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
rubygems activesupport
>=8.1.0.beta1, <8.1.2.1
>=8.0.0.beta1, <8.0.4.1
<7.2.3.1
8.1.2.1
8.0.4.1
7.2.3.1

Affected products

  • rails activesupport

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption
  • CWE-770 Allocation of Resources Without Limits or Throttling
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.

The maintainers of rails/rails published their own advisory on GitHub. Reviewed sources take precedence over it.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.