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Fencer Vulns
medium 5.9

CVE-2024-21647 json

HTTP Request/Response Smuggling in puma

published 2024-01-08 2 y ago modified 2026-09-10 1 mo ago also GHSA-c2f4-cvqm-65w2 , EUVD-2024-0323

cvss
5.9
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.0%
EPSS 1.0% chance of exploitation in 30 days, percentile 61%
public exploits
0
none known

Summary

Puma is a web server for Ruby/Rack applications built for parallelism. Prior to version 6.4.2, puma exhibited incorrect behavior when parsing chunked transfer encoding bodies in a way that allowed HTTP request smuggling. Fixed versions limits the size of chunk extensions. Without this limit, an attacker could cause unbounded resource (CPU, network bandwidth) consumption. This vulnerability has been fixed in versions 6.4.2 and 5.6.8.

Patch / fix

  • rubygems puma 5.6.8, 6.4.2
  • puma puma 5.6.8, 6.4.2
  • puma Debian 12 5.6.5-3+deb12u1
  • puma Debian 14, Debian 13 6.4.2-1

debian advisories DEBIAN-CVE-2024-21647

  • puma Ubuntu Pro 20.04 LTS 3.12.4-1ubuntu2+esm1
  • puma Ubuntu Pro 22.04 LTS 5.5.2-2ubuntu2+esm1

ubuntu advisories UBUNTU-CVE-2024-21647

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • foreman satellite utils 6.15, satellite capsule 6.15, satellite 6.15 3.9.1.6-1.el8sat
  • foreman-cli satellite utils 6.15, satellite 6.15 3.9.1.6-1.el8sat
  • foreman-ec2 satellite 6.15 3.9.1.6-1.el8sat
  • foreman-pcp satellite 6.15 3.9.1.6-1.el8sat
  • puppetserver satellite capsule 6.15, satellite 6.15 7.14.0-1.el8sat
  • rubygem-puma satellite 6.15 6.4.2-1.el8sat
  • foreman-ovirt satellite 6.15 3.9.1.6-1.el8sat
  • foreman-redis satellite 6.15 3.9.1.6-1.el8sat

red hat advisories RHSA-2024:2010

  • rubygem-puma SLE High Availability Extension 15 SP7, SLE High Availability Extension 15 SP6, openSUSE Leap 15.6 5.6.9-150600.18.3.1
  • rubygem-puma SLE High Availability Extension 15 SP5, SLE High Availability Extension 15 SP4, SLE High Availability Extension 15 SP3 5.6.9-150000.3.18.1
  • rubygem-puma SLE High Availability Extension 15 SP5, SLE High Availability Extension 15 SP4, SLE High Availability Extension 15 SP3 +2 more 4.3.12-150000.3.15.1

suse advisories SUSE-SU-2025:03467-1SUSE-SU-2025:03466-1SUSE-SU-2024:3644-1

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-2024-21647 updated cvss 7.5

rubygem-puma: HTTP request smuggling when parsing chunked Transfer-Encoding Bodies

  • Red Hat Storage 3 rubygem-puma
    affected: no fix planned “Out of support scope”
  • Red Hat Satellite 6.15 for RHEL 8 rubygem-puma 6.4.2-1.el8sat
    fixed: vendor fix RHSA-2024:2010
  • Red Hat Satellite 6 tfm-rubygem-puma Red Hat Satellite 6.15 for RHEL 8 cjson 1.7.14-5.el8sat, libsolv 0.7.22-6.el8pc, katello 4.11.0-1.el8sat, libcomps 0.1.18-8.el8pc, python-jq 1.6.0-3.el8pc, foreman 3.9.1.6-1.el8sat, +678 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
no
Technical impact
partial
Assessed
18 mo ago

Exploit prediction

0.96% chance of exploitation in the next 30 days, higher than 61% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
GitHub 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
rubygems puma
>=6.0.0, <6.4.2
<5.6.8
6.4.2
5.6.8

Affected products

  • puma puma

Classification

Weakness
  • CWE-444 Inconsistent Interpretation of HTTP Requests

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.