Back
CVE-2026-47736
Puma PROXY Protocol v1 Parser Allows Remote Memory Exhaustion
High7.5EPSS 0.35%
- Published
- Updated
- Reserved
- Assigned by
- GitHub_M
Description
Puma is a Ruby/Rack web server built for parallelism. From 5.5.0 until 7.2.1 and 8.0.2, when PROXY protocol v1 support is enabled, Puma reads incoming bytes into an internal buffer while waiting for CRLF to determine whether a PROXY v1 line is present, allowing an attacker that continuously sends bytes without CRLF to cause unbounded in-process memory growth and additional CPU cost from repeatedly scanning the growing buffer. This issue is fixed in versions 7.2.1 and 8.0.2.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| NVDNVD · Deferred | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 0.35% · top 72% of all CVEs (5 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: yes · Technical impact: partial
Loading the EPSS history…
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.
Weakness
Affected products
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- RubyGemspumaGHSA-qpgp-93vx-g8v8 (opens in a new tab)
References (5)
- https://github.com/puma/puma/security/advisories/GHSA-qpgp-93vx-g8v8 (opens in a new tab)x_refsource_CONFIRM
- https://github.com/puma/puma/commit/439c6136d9c2275721b7864db3ee78af7c80889f (opens in a new tab)x_refsource_MISC
- https://github.com/puma/puma/commit/ebe9db3929ab8299d19c8f5b41e8ef4f4b22fa58 (opens in a new tab)x_refsource_MISC
- https://github.com/puma/puma/releases/tag/v7.2.1 (opens in a new tab)x_refsource_MISC
- https://github.com/puma/puma/releases/tag/v8.0.2 (opens in a new tab)x_refsource_MISC
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-qpgp-93vx-g8v8 (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-47736)Record last updated .