CVE catalog
CVE-2026-47736
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 C
- Severity
- High · CVSS 7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Published
- Source
- [NVD] · [CVE record]
- EPSS
- 0.35% · Oct 25, 2026
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.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | puma | sid | 8.0.2-3 | fixed |
| Debian | puma | forky | 8.0.2-3 | fixed |
| Debian | puma | trixie | 6.6.0-4 | vulnerable |
| Debian | puma | bookworm | 5.6.5-3+deb12u1 | vulnerable |
| Debian | puma | bookworm-security | 5.6.5-3+deb12u2 | fixed |
| Cpe | puma | Not reported | Not reported | vulnerable |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | puma | source | sid | 8.0.2-1 | not yet assigned | Not reported | Not reported |
| Debian | puma | source | forky | 8.0.2-1 | not yet assigned | Not reported | Not reported |
| Debian | puma | source | trixie | (unfixed) | not yet assigned | Not reported | Not reported |
| Debian | puma | source | bookworm | 5.6.5-3+deb12u2 | not yet assigned | Not reported | Not reported |
Notes
[trixie] puma: Minor issue
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [puma]Affected
Details (2)
5.6.5-3+deb12u1· amd64 · bookwormAffected · Fixed:
5.6.5-3+deb12u2nvd · puma · debian · bookworm; nvd · puma · debian · 12
5.6.5-3+deb12u1· arm64 · bookwormAffected · Fixed:
5.6.5-3+deb12u2nvd · puma · debian · bookworm; nvd · puma · debian · 12
[Debian 13 (Trixie)]
- [puma]Affected
Details (2)
6.6.0-4· amd64 · trixieAffected
nvd · puma · debian · 13
6.6.0-4· arm64 · trixieAffected
nvd · puma · debian · 13
Observed:
References
- [https://nvd.nist.gov/vuln/detail/CVE-2026-47736]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2026-47736]
- [https://security-tracker.debian.org/tracker/CVE-2026-47736]
- [https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-47736.json]
[Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX]