CVE-2024-21647

unknown

Published 2024-01-08 · Modified 2026-02-04

💬 Discuss on Community ✚ Propose mitigation

CVSS v3

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CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v4 NEW

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not yet in upstream

VIR risk

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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.

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

OS	Version	Status	Fixed in
sles		affected
debian	bookworm	fixed	`5.6.5-3+deb12u1`
debian	bullseye	fixed	`4.3.8-1+deb11u3`
debian	forky	fixed	`6.4.2-1`
debian	sid	fixed	`6.4.2-1`
debian	trixie	fixed	`6.4.2-1`

Package impact

Ecosystem	Package	Vulnerable	Fixed
RubyGems	puma	`<~> 5.6.8`	`~> 5.6.8`
RubyGems	puma	`>=6.0.0,<6.4.2`	`6.4.2`
RubyGems	puma	`<5.6.8`	`5.6.8`

References

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

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