GHSA-r995-q44h-hr64 CVE-2025-6442
Ruby WEBrick read_headers method can lead to HTTP Request/Response Smuggling
- Severity
- 6.5 / 10
- Medium · CVSS 3.0
- Exploit chance (EPSS)
- 0.50%
- Chance of exploitation in the next 30 days. Higher than 42.47% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-444 Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
- Fix
1.8.2- Upgrade webrick to this version or later
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 versions
RubyGems
| Package | Vulnerable | Fixed in |
|---|---|---|
| webrick | < 1.8.2 |
1.8.2 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
webrick RubyGems → 1.8.2
- bundler
bundle update webrick # Gemfile: gem "webrick", ">= 1.8.2"
Severity breakdown
CVSS 3.0 6.5
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- High
- Availability
- None
Weakness
CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination.
How to prevent it
- Implementation: Use a web server that employs a strict HTTP parsing procedure, such as Apache [REF-433].
- Implementation: Use only SSL communication.
- Implementation: Terminate the client session after each request.
- System Configuration: Turn all pages to non-cacheable.
References
Advisories
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-6f62-3596-g6w7 HTTP Request Smuggling in ruby webrick | High | Also affects webrick |
| GHSA-gwfg-cqmg-cf8f WEBRick vulnerable to HTTP Request/Response Smuggling | High | Also affects webrick |
| GHSA-369m-2gv6-mw28 WEBrick RCE Vulnerability | High | Also affects webrick |
| GHSA-wfrc-r6c6-7j9r WEBrick Denial of Service Vulnerability | High | Also affects webrick |
| GHSA-6mq2-37j5-w6r6 WEBrick Improper Input Validation vulnerability | Medium | Also affects webrick |
| EEF-CVE-2026-114216 Chunk extensions accept bare LF and CR, enabling request smuggling in Bandit | Not rated yet | Same weakness, CWE-444 |
| RUSTSEC-2026-0388 Pingora HTTP/2 :authority and Host header mismatch enables cache poisoning and host-based access control bypass | Not rated yet | Same weakness, CWE-444 |
| GHSA-pqxq-w44r-73xw AIOHTTP: Pure-Python parser request smuggling | Medium | Same weakness, CWE-444 |
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