CVE-2025-6442

unknown

Published 2025-06-26 · Modified 2025-06-30

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CVSS v3

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CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N

CVSS v4 NEW

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not yet in upstream

VIR risk

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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.

Predictions

Exploit likelihood

30%

Patch ETA

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Heuristic predictions, AS-IS, for prioritization only.

Mitigations

No mitigations published for this CVE yet.

The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.

✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here with source_tier=community-verified.

OS impact

SUSE Affected 1 release

Version	Status	Fixed in
—	Affected	—

Debian Mixed 4 releases

Version	Status	Fixed in
trixie	Fixed	`1.9.1-1`
sid	Fixed	`1.9.1-1`
forky	Fixed	`1.9.1-1`
bookworm	Affected	—

Package impact

Ecosystem	Package	Vulnerable	Fixed
RubyGems	webrick	`<>= 1.8.2`	`>= 1.8.2`
RubyGems	webrick	`<1.8.2`	`1.8.2`

References

Community-verified mitigations for this CVE will appear above when contributors publish them.

Verify integrity in audit chain (admin only). AS-IS.