CVE catalog
CVE-2026-49854
Tornado is a Python web framework and asynchronous networking library. Prior to 6.5.6, the optional native extension tornado.speedups implemented websocket_mask without validating that the mask argume
- Severity
- Medium · CVSS 5.3
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N - Published
- Source
- [NVD] · [CVE record]
- EPSS
- 0.42% · Oct 25, 2026
Tornado is a Python web framework and asynchronous networking library. Prior to 6.5.6, the optional native extension tornado.speedups implemented websocket_mask without validating that the mask argument is exactly four bytes, allowing the C function to read up to three bytes beyond the provided buffer when reached through Tornado XSRF token decoding with the native extension active. This issue is fixed in version 6.5.6.
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 | python-tornado | sid | 6.5.5-5 | vulnerable |
| Debian | python-tornado | forky | 6.5.5-5 | vulnerable |
| Debian | python-tornado | trixie | 6.4.2-3+deb13u2 | vulnerable |
| Debian | python-tornado | trixie-security | 6.4.2-3+deb13u2 | vulnerable |
| Debian | python-tornado | bookworm | 6.2.0-3+deb12u4 | vulnerable |
| Debian | python-tornado | bookworm-security | 6.2.0-3+deb12u4 | vulnerable |
| Cpe | python-tornado | Not reported | Not reported | vulnerable |
| Ubuntu | python-tornado | pro | 6.1.0-1build1 | vulnerable |
| Ubuntu | python-tornado | pro | 6.1.0-2 | vulnerable |
| Ubuntu | python-tornado | pro | 6.1.0-3 | vulnerable |
| Ubuntu | python-tornado | pro | 6.1.0-3build1 | vulnerable |
| Ubuntu | python-tornado | pro | 6.1.0-3ubuntu0.1~esm1 | vulnerable |
| Ubuntu | python-tornado | pro | 6.1.0-3ubuntu0.1~esm2 | vulnerable |
| Ubuntu | python-tornado | pro | 6.1.0-3ubuntu0.1~esm4 | vulnerable |
| Ubuntu | python-tornado | pro | 6.1.0-3ubuntu0.1~esm5 | vulnerable |
| Ubuntu | python-tornado | pro | 6.1.0-3ubuntu0.1~esm6 | vulnerable |
| Ubuntu | python-tornado | 24.04 | 6.3.2-1 | vulnerable |
| Ubuntu | python-tornado | 24.04 | 6.4.0-0ubuntu1 | vulnerable |
| Ubuntu | python-tornado | 24.04 | 6.4.0-1 | vulnerable |
| Ubuntu | python-tornado | 24.04 | 6.4.0-1build1 | vulnerable |
| Ubuntu | python-tornado | 24.04 | 6.4.0-1ubuntu0.1 | vulnerable |
| Ubuntu | python-tornado | 24.04 | 6.4.0-1ubuntu0.2 | vulnerable |
| Ubuntu | python-tornado | 24.04 | 6.4.0-1ubuntu0.4 | vulnerable |
| Ubuntu | python-tornado | 24.04 | 6.4.0-1ubuntu0.5 | vulnerable |
| Ubuntu | python-tornado | 24.04 | 6.4.0-1ubuntu0.6 | vulnerable |
| Ubuntu | python-tornado | 26.10 | 6.5.4-0.1 | vulnerable |
| Ubuntu | python-tornado | 26.10 | 6.5.5-2 | vulnerable |
| Ubuntu | python-tornado | 26.10 | 6.5.5-4 | vulnerable |
| Ubuntu | python-tornado | 26.10 | 6.5.5-5 | vulnerable |
| Ubuntu | python-tornado | 26.10 | 6.5.5-5ubuntu1.1 | vulnerable |
| Ubuntu | python-tornado | 26.04 | 6.4.2-3 | vulnerable |
| Ubuntu | python-tornado | 26.04 | 6.5.2-3 | vulnerable |
| Ubuntu | python-tornado | 26.04 | 6.5.4-0.1 | vulnerable |
| Ubuntu | python-tornado | 26.04 | 6.5.4-0.1ubuntu0.1 | vulnerable |
| Ubuntu | python-tornado | 26.04 | 6.5.4-0.1ubuntu0.2 | vulnerable |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | python-tornado | source | sid | (unfixed) | not yet assigned | Not reported | [1142277] |
| Debian | python-tornado | source | forky | (unfixed) | not yet assigned | Not reported | [1142277] |
| Debian | python-tornado | source | trixie | (unfixed) | not yet assigned | Not reported | [1142277] |
| Debian | python-tornado | source | bookworm | (unfixed) | not yet assigned | Not reported | [1142277] |
Notes
[trixie] python-tornado: Minor issue
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [python3-tornado]Affected
Source package: [python-tornado]
Details (4)
6.2.0-3+deb12u4· amd64 · bookwormAffected
nvd · python-tornado · debian · bookworm; nvd · python-tornado · debian · 12
6.2.0-3+deb12u4· arm64 · bookwormAffected
nvd · python-tornado · debian · bookworm; nvd · python-tornado · debian · 12
6.2.0-3+deb12u4· amd64 · bookworm-securityAffected
nvd · python-tornado · debian · bookworm; nvd · python-tornado · debian · 12
6.2.0-3+deb12u4· arm64 · bookworm-securityAffected
nvd · python-tornado · debian · bookworm; nvd · python-tornado · debian · 12
- [python-tornado-doc]Affected
Source package: [python-tornado]
Details (4)
6.2.0-3+deb12u4· all · bookwormAffected
nvd · python-tornado · debian · bookworm; nvd · python-tornado · debian · 12
6.2.0-3+deb12u4· all · bookwormAffected
nvd · python-tornado · debian · bookworm; nvd · python-tornado · debian · 12
6.2.0-3+deb12u4· all · bookworm-securityAffected
nvd · python-tornado · debian · bookworm; nvd · python-tornado · debian · 12
6.2.0-3+deb12u4· all · bookworm-securityAffected
nvd · python-tornado · debian · bookworm; nvd · python-tornado · debian · 12
[Debian 13 (Trixie)]
- [python3-tornado]Affected
Source package: [python-tornado]
Details (4)
6.4.2-3+deb13u2· amd64 · trixieAffected
nvd · python-tornado · debian · 13
6.4.2-3+deb13u2· arm64 · trixieAffected
nvd · python-tornado · debian · 13
6.4.2-3+deb13u2· amd64 · trixie-securityAffected
nvd · python-tornado · debian · 13
6.4.2-3+deb13u2· arm64 · trixie-securityAffected
nvd · python-tornado · debian · 13
- [python-tornado-doc]Affected
Source package: [python-tornado]
Details (4)
6.4.2-3+deb13u2· all · trixieAffected
nvd · python-tornado · debian · 13
6.4.2-3+deb13u2· all · trixieAffected
nvd · python-tornado · debian · 13
6.4.2-3+deb13u2· all · trixie-securityAffected
nvd · python-tornado · debian · 13
6.4.2-3+deb13u2· all · trixie-securityAffected
nvd · python-tornado · debian · 13
Observed:
References
- [https://ftp.suse.com/pub/projects/security/csaf/suse-su-2026_4580-1.json]
- [https://github.com/tornadoweb/tornado/commit/96dc88c2a05705287856b2cd6b4b4034f9a6aaac]
- [https://github.com/tornadoweb/tornado/pull/3626]
- [https://github.com/tornadoweb/tornado/releases/tag/v6.5.6]
- [https://github.com/tornadoweb/tornado/security/advisories/GHSA-cx3h-4qpv-8hc9]
- [https://nvd.nist.gov/vuln/detail/CVE-2026-49854]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2026-49854]
- [https://osv.dev/vulnerability/UBUNTU-CVE-2026-49854]
- [https://security-tracker.debian.org/tracker/CVE-2026-49854]
- [https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-49854.json]
[Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX]