Description
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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| puma | puma | < 5.6.8, >= 6.0.0, < 6.4.2 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | puma | 6.4.2-1 | — |
| Debian 13 | puma | 6.4.2-1 | — |
| Debian 12 | puma | 5.6.5-3+deb12u1 | — |
| Debian 11 | puma | 4.3.8-1+deb11u3 | DLA-3947-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 22.04 LTS | puma | 5.5.2-2ubuntu2+esm1 | USN-6682-1 |
| Ubuntu Pro 20.04 LTS | puma | 3.12.4-1ubuntu2+esm1 | USN-6682-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat Satellite Utils 6 | foreman +1 | 3.9.1.6-1.el8sat | RHSA-2024:2010 |
| Red Hat Satellite Capsule 6 | foreman +1 | 3.9.1.6-1.el8sat | RHSA-2024:2010 |
| Red Hat Satellite Capsule 6 | puppetserver | 7.14.0-1.el8sat | RHSA-2024:2010 |
| Red Hat Satellite Capsule 6 | python-aiohttp +1 | 3.9.2-1.el8pc | RHSA-2024:2010 |
| Red Hat Satellite Capsule 6 | python-django +1 | 4.2.9-1.el8pc | RHSA-2024:2010 |
| Red Hat Satellite Capsule 6 | python-galaxy-importer +1 | 0.4.19-2.el8pc | RHSA-2024:2010 |
| Red Hat Satellite Capsule 6 | python-jinja2 +1 | 3.1.3-1.el8pc | RHSA-2024:2010 |
| Red Hat Satellite Capsule 6 | python-pycryptodomex +1 | 3.20.0-1.el8pc | RHSA-2024:2010 |
| Red Hat Satellite Capsule 6 | python-pygments +1 | 2.17.0-1.el8pc | RHSA-2024:2010 |
| Red Hat Satellite Capsule 6 | rubygem-activesupport | 6.1.7.6-1.el8sat | RHSA-2024:2010 |
| Red Hat Satellite 6 | foreman +14 | 3.9.1.6-1.el8sat | RHSA-2024:2010 |
| Red Hat Satellite 6 | puppetserver | 7.14.0-1.el8sat | RHSA-2024:2010 |
| Red Hat Satellite 6 | python-aiohttp +1 | 3.9.2-1.el8pc | RHSA-2024:2010 |
| Red Hat Satellite 6 | python-django +1 | 4.2.9-1.el8pc | RHSA-2024:2010 |
| Red Hat Satellite 6 | python-galaxy-importer +1 | 0.4.19-2.el8pc | RHSA-2024:2010 |
| Red Hat Satellite 6 | python-jinja2 +1 | 3.1.3-1.el8pc | RHSA-2024:2010 |
| Red Hat Satellite 6 | python-pycryptodomex +1 | 3.20.0-1.el8pc | RHSA-2024:2010 |
| Red Hat Satellite 6 | python-pygments +1 | 2.17.0-1.el8pc | RHSA-2024:2010 |
| Red Hat Satellite 6 | rubygem-activesupport | 6.1.7.6-1.el8sat | RHSA-2024:2010 |
| Red Hat Satellite 6 | rubygem-audited | 5.4.2-1.el8sat | RHSA-2024:2010 |
| Red Hat Satellite 6 | rubygem-puma | 6.4.2-1.el8sat | RHSA-2024:2010 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | rubygem-puma | 5.6.9-150600.18.3.1 | SUSE-SU-2025:03467-1 |
| SLES 15 SP6 | rubygem-puma | 5.6.9-150600.18.3.1 | SUSE-SU-2025:03467-1 |
| SLES 15 SP5 | rubygem-puma | 4.3.12-150000.3.15.1 | SUSE-SU-2025:03466-1, SUSE-SU-2024:3644-1 |
| SLES 15 SP4 | rubygem-puma | 4.3.12-150000.3.15.1 | SUSE-SU-2025:03466-1, SUSE-SU-2024:3644-1 |
| SLES 15 SP3 | rubygem-puma | 4.3.12-150000.3.15.1 | SUSE-SU-2025:03466-1, SUSE-SU-2024:3644-1 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP2 | rubygem-puma | 4.3.12-150000.3.15.1 | SUSE-SU-2024:3644-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap 15.6 | rubygem-puma | 5.6.9-150600.18.3.1 | SUSE-SU-2025:03467-1 |
| openSUSE Leap 15.5 | rubygem-puma | 4.3.12-150000.3.15.1 | SUSE-SU-2024:3644-1 |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | ruby3.2-puma | 6.4.2-r0 | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| RubyGems | puma | >= 6.0.0, < 6.4.2 | 6.4.2 | GHSA-c2f4-cvqm-65w2 |
| RubyGems | puma | < 5.6.8 | 5.6.8 | GHSA-c2f4-cvqm-65w2 |
Advisories 7
- RHSA-2024:2010 Red Hat Security Advisory: Satellite 6.15.0 release Red Hat Security Advisories (RHSA) · Oct 13, 2026
- USN-6682-1 puma vulnerabilities Ubuntu Security Notices (USN) · Apr 27, 2026
- SUSE-SU-2025:03466-1 Security update for rubygem-puma SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2025:03467-1 Security update for rubygem-puma SUSE / openSUSE Security Updates · Mar 23, 2026
- DLA-3947-1 puma - security update Debian Security (DSA / DLA) · Mar 9, 2026
- SUSE-SU-2024:3644-1 Security update for rubygem-puma SUSE / openSUSE Security Updates · Feb 4, 2026
- WID-SEC-2024-0949 Red Hat Satellite: Mehrere Schwachstellen BSI CERT-Bund (WID) · Jan 26, 2026