Impact

Prior to versions 6.4.2 and 5.6.8, puma exhibited dangerous behavior when parsing chunked transfer encoding bodies.

Fixed versions limit the size of chunk extensions. Without this limit, an attacker could cause unbounded resource (CPU, network bandwidth) consumption.

Patches

The vulnerability has been fixed in 6.4.2 and 5.6.8.

Workarounds

No known workarounds.

References

• HTTP Request Smuggling
• Open an issue in Puma
• See our security policy

References

• GHSA-c2f4-cvqm-65w2
• https://nvd.nist.gov/vuln/detail/CVE-2024-21647
• puma/puma@5fc43d7
• puma/puma@60d5ee3
• puma/puma@bbb880f
• https://github.com/rubysec/ruby-advisory-db/blob/master/gems/puma/CVE-2024-21647.yml