Description
Ruby WEBrick read_header HTTP Request Smuggling Vulnerability. This vulnerability allows remote attackers to smuggle arbitrary HTTP requests on affected installations of Ruby WEBrick. This issue is exploitable when the product is deployed behind an HTTP proxy that fulfills specific conditions.
The specific flaw exists within the read_headers method. The issue results from the inconsistent parsing of terminators of HTTP headers. An attacker can leverage this vulnerability to smuggle arbitrary HTTP requests. Was ZDI-CAN-21876.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Ruby | WEBrick | 1.8.1 | — |
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 | ruby-webrick | 1.9.1-1 | — |
| Debian 13 | ruby-webrick | 1.9.1-1 | — |
| Debian 12 | ruby-webrick | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.04 LTS | ruby-webrick | 1.9.1-1 | — |
| Ubuntu 25.10 | ruby-webrick | 1.9.1-1 | — |
| Ubuntu 24.04 LTS | ruby-webrick | 1.8.1-1ubuntu0.2 | USN-7709-1 |
| Ubuntu 22.04 LTS | ruby-webrick | 1.7.0-3ubuntu0.2 | USN-7709-1 |
| Ubuntu 20.04 LTS | jruby | No fix yet | — |
Show 6 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | jruby | No fix yet | — |
| Ubuntu 16.04 LTS | jruby | No fix yet | — |
| Ubuntu Pro 20.04 LTS | ruby2.7 | 2.7.0-5ubuntu1.18+esm3 | USN-7840-1 |
| Ubuntu Pro 18.04 LTS | ruby2.5 | 2.5.1-1ubuntu1.16+esm6 | USN-7840-1 |
| Ubuntu Pro 16.04 LTS | ruby2.3 | 2.3.1-2~ubuntu16.04.16+esm11 | USN-7840-1 |
| Ubuntu Pro 14.04 LTS | jruby | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | ruby2.5 | 2.5.9-150700.24.3.1 | SUSE-SU-2025:4264-1 |
| SLES 15 SP6 | ruby2.5 | 2.5.9-150000.4.46.1 | SUSE-SU-2025:02739-1 |
| SLES 15 SP5 | ruby2.5 | 2.5.9-150000.4.46.1 | SUSE-SU-2025:02739-2 |
| SLES 15 SP4 | ruby2.5 | 2.5.9-150000.4.46.1 | SUSE-SU-2025:02739-2 |
| SLES 15 SP3 | ruby2.5 | 2.5.9-150000.4.46.1 | SUSE-SU-2025:02739-2 |
Show 9 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 15 SP5 | ruby2.5 | 2.5.9-150000.4.46.1 | SUSE-SU-2025:02739-2 |
| SLES for SAP 15 SP4 | ruby2.5 | 2.5.9-150000.4.46.1 | SUSE-SU-2025:02739-2 |
| SLES for SAP 15 SP3 | ruby2.5 | 2.5.9-150000.4.46.1 | SUSE-SU-2025:02739-2 |
| SLE HPC 15 SP5 | ruby2.5 | 2.5.9-150000.4.46.1 | SUSE-SU-2025:02739-2 |
| SLE HPC 15 SP4 | ruby2.5 | 2.5.9-150000.4.46.1 | SUSE-SU-2025:02739-2 |
| SLE HPC 15 SP3 | ruby2.5 | 2.5.9-150000.4.46.1 | SUSE-SU-2025:02739-2 |
| SUSE Manager Server 4.3 | ruby2.5 | 2.5.9-150000.4.46.1 | SUSE-SU-2025:02739-2 |
| SUSE Manager Proxy 4.3 | ruby2.5 | 2.5.9-150000.4.46.1 | SUSE-SU-2025:02739-2 |
| SUSE Enterprise Storage 7.1 | ruby2.5 | 2.5.9-150000.4.46.1 | SUSE-SU-2025:02739-2 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap 15.6 | ruby2.5 | 2.5.9-150000.4.46.1 | SUSE-SU-2025:02739-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | ruby3.2 +5 | 3.2.8-184.amzn2023.0.2 | ALAS2023-2025-1115 |
| Amazon Linux 2023 | ruby3.2-rubygem-bigdecimal | 3.1.3-184.amzn2023.0.2 | ALAS2023-2025-1115 |
| Amazon Linux 2023 | ruby3.2-rubygem-bundler | 2.4.19-184.amzn2023.0.2 | ALAS2023-2025-1115 |
| Amazon Linux 2023 | ruby3.2-rubygem-io-console | 0.6.0-184.amzn2023.0.2 | ALAS2023-2025-1115 |
| Amazon Linux 2023 | ruby3.2-rubygem-irb | 1.6.2-184.amzn2023.0.2 | ALAS2023-2025-1115 |
| Amazon Linux 2023 | ruby3.2-rubygem-json | 2.6.3-184.amzn2023.0.2 | ALAS2023-2025-1115 |
| Amazon Linux 2023 | ruby3.2-rubygem-minitest | 5.25.1-184.amzn2023.0.2 | ALAS2023-2025-1115 |
| Amazon Linux 2023 | ruby3.2-rubygem-power_assert | 2.0.3-184.amzn2023.0.2 | ALAS2023-2025-1115 |
| Amazon Linux 2023 | ruby3.2-rubygem-psych | 5.0.1-184.amzn2023.0.2 | ALAS2023-2025-1115 |
| Amazon Linux 2023 | ruby3.2-rubygem-rake | 13.0.6-184.amzn2023.0.2 | ALAS2023-2025-1115 |
| Amazon Linux 2023 | ruby3.2-rubygem-rbs | 2.8.2-184.amzn2023.0.2 | ALAS2023-2025-1115 |
| Amazon Linux 2023 | ruby3.2-rubygem-rdoc | 6.5.1.1-184.amzn2023.0.2 | ALAS2023-2025-1115 |
| Amazon Linux 2023 | ruby3.2-rubygem-rexml | 3.3.9-184.amzn2023.0.2 | ALAS2023-2025-1115 |
| Amazon Linux 2023 | ruby3.2-rubygem-rss | 0.3.1-184.amzn2023.0.2 | ALAS2023-2025-1115 |
| Amazon Linux 2023 | ruby3.2-rubygem-test-unit | 3.5.7-184.amzn2023.0.2 | ALAS2023-2025-1115 |
| Amazon Linux 2023 | ruby3.2-rubygem-typeprof | 0.21.3-184.amzn2023.0.2 | ALAS2023-2025-1115 |
| Amazon Linux 2023 | ruby3.2-rubygems +1 | 3.4.19-184.amzn2023.0.2 | ALAS2023-2025-1115 |
| Amazon Linux 2 | ruby +5 | 2.0.0.648-36.amzn2.0.15 | ALAS2-2025-2931 |
| Amazon Linux 2 | rubygem-bigdecimal | 1.2.0-36.amzn2.0.15 | ALAS2-2025-2931 |
| Amazon Linux 2 | rubygem-io-console | 0.4.2-36.amzn2.0.15 | ALAS2-2025-2931 |
| Amazon Linux 2 | rubygem-json | 1.7.7-36.amzn2.0.15 | ALAS2-2025-2931 |
| Amazon Linux 2 | rubygem-minitest | 4.3.2-36.amzn2.0.15 | ALAS2-2025-2931 |
| Amazon Linux 2 | rubygem-psych | 2.0.0-36.amzn2.0.15 | ALAS2-2025-2931 |
| Amazon Linux 2 | rubygem-rake | 0.9.6-36.amzn2.0.15 | ALAS2-2025-2931 |
| Amazon Linux 2 | rubygem-rdoc | 4.0.0-36.amzn2.0.15 | ALAS2-2025-2931 |
| Amazon Linux 2 | rubygems +1 | 2.0.14.1-36.amzn2.0.15 | ALAS2-2025-2931 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | ruby | 3.3.5-4 | — |
| Azure Linux 3 | rubygem-webrick | 1.8.1-2 | — |
| Azure Linux 2 (CBL-Mariner) | ruby | 3.1.7-2 | — |
| Azure Linux 2 (CBL-Mariner) | rubygem-webrick | 1.7.0-2 | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| RubyGems | webrick | < 1.8.2 | 1.8.2 | GHSA-r995-q44h-hr64 |
Advisories 9
- WID-SEC-2025-2475 Apple macOS: Mehrere Schwachstellen BSI CERT-Bund (WID) · Oct 11, 2026
- USN-7840-1 ruby2.3, ruby2.5, ruby2.7 vulnerabilities Ubuntu Security Notices (USN) · Jun 25, 2026
- USN-7709-1 ruby-webrick vulnerability Ubuntu Security Notices (USN) · Apr 27, 2026
- SUSE-SU-2025:4264-1 Security update for ruby2.5 SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2025:02739-2 Security update for ruby2.5 SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2025:02739-1 Security update for ruby2.5 SUSE / openSUSE Security Updates · Feb 4, 2026
- NCSC-2025-0351 Kwetsbaarheden verholpen in Apple MacOS NCSC-NL (Netherlands) · Nov 4, 2025
- ALAS2023-2025-1115 Moderate: ruby3.2 security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Aug 8, 2025
- ALAS2-2025-2931 Moderate: ruby security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Jul 30, 2025
References
- ZDI-25-414
- vendor-provided URL vendor-advisory