# CVE-2025-47287: Tornado vulnerable to excessive logging caused by malformed multipart form data > Remote attackers can cause denial of service in Tornado by sending malformed multipart form data that triggers excessive synchronous logging. - **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 15 May 2025 - **Updated:** 29 May 2025 - **Also known as:** ALSA-2025:8135, ALSA-2025:8136, AZL-61860, AZL-61866, CLEANSTART-2026-XW62361, CLSA-2026-1787299006, DEBIAN-CVE-2025-47287, DLA-4188-1, DSA-5938-1, ECHO-6b4d-4550-0606, GHSA-7cx3-6m66-7c5m, MGASA-2025-0282, OESA-2025-1554, OESA-2025-1555, OESA-2025-1614, OESA-2025-1615, OESA-2025-1905, OESA-2025-2580, PYSEC-2026-1974, RHSA-2025:8135, RHSA-2025:8136, RHSA-2025:8223, RHSA-2025:8226, RHSA-2025:8664, RLSA-2025:8135, RLSA-2025:8136, ROOT-APP-PYPI-CVE-2025-47287, SUSE-SU-2025:01649-1, SUSE-SU-2025:01649-2, SUSE-SU-2025:01726-1, SUSE-SU-2025:01726-2, SUSE-SU-2025:01732-1, SUSE-SU-2025:20430-1, UBUNTU-CVE-2025-47287, USN-7547-1, openSUSE-SU-2025:15153-1 ## What is CVE-2025-47287? CVE-2025-47287 is a high-severity denial of service vulnerability in Debian Debian Linux, published on 15 May 2025. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description Tornado is a Python web framework and asynchronous networking library. When Tornado's ``multipart/form-data`` parser encounters certain errors, it logs a warning but continues trying to parse the remainder of the data. This allows remote attackers to generate an extremely high volume of logs, constituting a DoS attack. This DoS is compounded by the fact that the logging subsystem is synchronous. All versions of Tornado prior to 6.5.0 are affected. The vulnerable parser is enabled by default. Upgrade to Tornado version 6.50 to receive a patch. As a workaround, risk can be mitigated by blocking `Content-Type: multipart/form-data` in a proxy. Weakness: CWE-770 (Allocation of Resources Without Limits or Throttling) ## Which versions are affected by CVE-2025-47287? 3 open source packages ship an affected version, including tornado. It affects 2 products. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `tornado` | PyPI | All versions | 6.5 | | `tornado` | PyPI | All versions | 6.5 | | `tornado` | PyPI | All versions | 6.5 | | `python3-tornado` | AlmaLinux:10 | All versions | 6.4.2-1.el10_0.1 | | `python3-tornado` | AlmaLinux:9 | All versions | 6.4.2-2.el9_6.2 | | `python-tornado` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.4.2-1.el10_0.1 | | `python-tornado-debugsource` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.4.2-1.el10_0.1 | | `python3-tornado` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.4.2-1.el10_0.1 | | `python3-tornado-debuginfo` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.4.2-1.el10_0.1 | | `python-tornado` | Red Hat:enterprise_linux:9::appstream | All versions | 0:6.4.2-2.el9_6.2 | | `python-tornado-debugsource` | Red Hat:enterprise_linux:9::appstream | All versions | 0:6.4.2-2.el9_6.2 | | `python3-tornado` | Red Hat:enterprise_linux:9::appstream | All versions | 0:6.4.2-2.el9_6.2 | | `python3-tornado-debuginfo` | Red Hat:enterprise_linux:9::appstream | All versions | 0:6.4.2-2.el9_6.2 | | `python-tornado` | Red Hat:rhel_els:7 | All versions | 0:4.2.1-5.el7_9.1 | | `python-tornado-debuginfo` | Red Hat:rhel_els:7 | All versions | 0:4.2.1-5.el7_9.1 | | `python-tornado-doc` | Red Hat:rhel_els:7 | All versions | 0:4.2.1-5.el7_9.1 | | `python-tornado` | Red Hat:rhel_eus:9.2::appstream | All versions | 0:6.4.2-1.el9_2.1 | | `python-tornado-debugsource` | Red Hat:rhel_eus:9.2::appstream | All versions | 0:6.4.2-1.el9_2.1 | | `python3-tornado` | Red Hat:rhel_eus:9.2::appstream | All versions | 0:6.4.2-1.el9_2.1 | | `python3-tornado-debuginfo` | Red Hat:rhel_eus:9.2::appstream | All versions | 0:6.4.2-1.el9_2.1 | | `python-tornado` | Red Hat:rhel_eus:9.4::appstream | All versions | 0:6.4.2-1.el9_4.1 | | `python-tornado-debugsource` | Red Hat:rhel_eus:9.4::appstream | All versions | 0:6.4.2-1.el9_4.1 | | `python3-tornado` | Red Hat:rhel_eus:9.4::appstream | All versions | 0:6.4.2-1.el9_4.1 | | `python3-tornado-debuginfo` | Red Hat:rhel_eus:9.4::appstream | All versions | 0:6.4.2-1.el9_4.1 | | `python-tornado` | Rocky Linux:10 | All versions | 0:6.4.2-1.el10_0.1 | | `python-tornado` | Rocky Linux:9 | All versions | 0:6.4.2-2.el9_6.2 | | `python-tornado` | SUSE:Enterprise Storage 7.1 | All versions | 4.5.3-150000.3.10.1 | | `python-tornado` | SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | All versions | 4.5.3-150000.3.10.1 | | `python-tornado` | SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | All versions | 4.5.3-150000.3.10.1 | | `python-tornado6` | SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | All versions | 6.3.2-150400.9.9.1 | | `python-tornado` | SUSE:Linux Enterprise High Performance Computing 15 SP4-LTSS | All versions | 4.5.3-150000.3.10.1 | | `python-tornado6` | SUSE:Linux Enterprise High Performance Computing 15 SP4-LTSS | All versions | 6.3.2-150400.9.9.1 | | `python-tornado` | SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS | All versions | 4.5.3-150000.3.10.1 | | `python-tornado6` | SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS | All versions | 6.3.2-150400.9.9.1 | | `python-tornado` | SUSE:Linux Enterprise High Performance Computing 15 SP5-LTSS | All versions | 4.5.3-150000.3.10.1 | | `python-tornado6` | SUSE:Linux Enterprise High Performance Computing 15 SP5-LTSS | All versions | 6.3.2-150400.9.9.1 | | `python-tornado` | SUSE:Linux Enterprise Micro 5.2 | All versions | 4.5.3-150000.3.10.1 | | `python-tornado` | SUSE:Linux Enterprise Micro 5.3 | All versions | 4.5.3-150000.3.10.1 | | `python-tornado` | SUSE:Linux Enterprise Micro 5.4 | All versions | 4.5.3-150000.3.10.1 | | `python-tornado` | SUSE:Linux Enterprise Micro 5.5 | All versions | 4.5.3-150000.3.10.1 | Products: Debian Debian Linux, Tornadoweb Tornado. ## How do I fix CVE-2025-47287? Upgrade tornado to 6.5 or later. ## Is CVE-2025-47287 being exploited? There is no known exploitation of CVE-2025-47287 in the wild and no public exploit code. ## Other vulnerabilities in Debian Debian Linux - [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild) - [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild) - [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild) - [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild) - [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2025-47287 and fix it if it is affected. What it is: CVE-2025-47287 is a high-severity denial of service vulnerability in Debian Debian Linux, published on 15 May 2025. An attacker can exploit it over the internet without logging in, with no action from the victim. Exploitation: There is no known exploitation of CVE-2025-47287 in the wild and no public exploit code. Affected packages and fixed versions: - tornado (PyPI): affected all versions; fixed in 6.5 - tornado (PyPI): affected all versions; fixed in 6.5 - tornado (PyPI): affected all versions; fixed in 6.5 Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2025-47287/ (Markdown: https://insights.sbomify.com/CVE-2025-47287/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2025-47287 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-47287 - OSV: https://osv.dev/vulnerability/CVE-2025-47287 --- From sbomify Insights: https://insights.sbomify.com/CVE-2025-47287/ Summaries are generated and may contain mistakes; the official description above is the record.