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Vulnerability details: VCID-be89-uuxa-fyb5
Vulnerability ID VCID-be89-uuxa-fyb5
Aliases CVE-2026-31958
GHSA-qjxf-f2mg-c6mc
Summary Tornado is vulnerable to DoS due to too many multipart parts In versions of Tornado prior to 6.5.5, the only limit on the number of parts in `multipart/form-data` is the `max_body_size` setting (default 100MB). Since parsing occurs synchronously on the main thread, this creates the possibility of denial-of-service due to the cost of parsing very large multipart bodies with many parts. Tornado 6.5.5 introduces new limits on the size and complexity of multipart bodies, including a default limit of 100 parts per request. These limits are configurable if needed; see `tornado.httputil.ParseMultipartConfig`. It is also now possible to disable `multipart/form-data` parsing entirely if it is not required for the application.
Status Published
Exploitability 0.5
Weighted Severity 8.0
Risk 4.0
Affected and Fixed Packages Package Details
Weaknesses (4)
CWE-400 Uncontrolled Resource Consumption
CWE-770 Allocation of Resources Without Limits or Throttling
CWE-937 OWASP Top Ten 2013 Category A9 - Using Components with Known Vulnerabilities
CWE-1035 OWASP Top Ten 2017 Category A9 - Using Components with Known Vulnerabilities
System Score Found at
cvssv3 5.3 https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2026-31958.json
epss 0.0003 https://api.first.org/data/v1/epss?cve=CVE-2026-31958
epss 0.0003 https://api.first.org/data/v1/epss?cve=CVE-2026-31958
epss 0.0003 https://api.first.org/data/v1/epss?cve=CVE-2026-31958
epss 0.0003 https://api.first.org/data/v1/epss?cve=CVE-2026-31958
epss 0.0003 https://api.first.org/data/v1/epss?cve=CVE-2026-31958
epss 0.0003 https://api.first.org/data/v1/epss?cve=CVE-2026-31958
epss 0.00032 https://api.first.org/data/v1/epss?cve=CVE-2026-31958
epss 0.00032 https://api.first.org/data/v1/epss?cve=CVE-2026-31958
epss 0.00032 https://api.first.org/data/v1/epss?cve=CVE-2026-31958
epss 0.00032 https://api.first.org/data/v1/epss?cve=CVE-2026-31958
epss 0.00032 https://api.first.org/data/v1/epss?cve=CVE-2026-31958
epss 0.00032 https://api.first.org/data/v1/epss?cve=CVE-2026-31958
epss 0.00032 https://api.first.org/data/v1/epss?cve=CVE-2026-31958
epss 0.00032 https://api.first.org/data/v1/epss?cve=CVE-2026-31958
cvssv3.1 7.5 https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
cvssv3.1_qr HIGH https://github.com/advisories/GHSA-qjxf-f2mg-c6mc
cvssv3.1 7.5 https://github.com/tornadoweb/tornado
cvssv4 8.7 https://github.com/tornadoweb/tornado
generic_textual HIGH https://github.com/tornadoweb/tornado
cvssv3.1 7.5 https://github.com/tornadoweb/tornado/commit/119a195e290c43ad2d63a2cf012c29d43d6ed839
cvssv4 8.7 https://github.com/tornadoweb/tornado/commit/119a195e290c43ad2d63a2cf012c29d43d6ed839
generic_textual HIGH https://github.com/tornadoweb/tornado/commit/119a195e290c43ad2d63a2cf012c29d43d6ed839
cvssv3.1 7.5 https://github.com/tornadoweb/tornado/releases/tag/v6.5.5
cvssv4 8.7 https://github.com/tornadoweb/tornado/releases/tag/v6.5.5
generic_textual HIGH https://github.com/tornadoweb/tornado/releases/tag/v6.5.5
cvssv3.1 7.5 https://github.com/tornadoweb/tornado/security/advisories/GHSA-qjxf-f2mg-c6mc
cvssv3.1_qr HIGH https://github.com/tornadoweb/tornado/security/advisories/GHSA-qjxf-f2mg-c6mc
cvssv4 8.7 https://github.com/tornadoweb/tornado/security/advisories/GHSA-qjxf-f2mg-c6mc
generic_textual HIGH https://github.com/tornadoweb/tornado/security/advisories/GHSA-qjxf-f2mg-c6mc
ssvc Track https://github.com/tornadoweb/tornado/security/advisories/GHSA-qjxf-f2mg-c6mc
cvssv3.1 7.5 https://lists.debian.org/debian-lts-announce/2026/04/msg00000.html
cvssv4 8.7 https://lists.debian.org/debian-lts-announce/2026/04/msg00000.html
generic_textual HIGH https://lists.debian.org/debian-lts-announce/2026/04/msg00000.html
cvssv3.1 7.5 https://nvd.nist.gov/vuln/detail/CVE-2026-31958
cvssv4 8.7 https://nvd.nist.gov/vuln/detail/CVE-2026-31958
generic_textual HIGH https://nvd.nist.gov/vuln/detail/CVE-2026-31958
Reference id Reference type URL
https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2026-31958.json
https://api.first.org/data/v1/epss?cve=CVE-2026-31958
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-31958
https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
https://github.com/tornadoweb/tornado
https://github.com/tornadoweb/tornado/commit/119a195e290c43ad2d63a2cf012c29d43d6ed839
https://github.com/tornadoweb/tornado/releases/tag/v6.5.5
https://github.com/tornadoweb/tornado/security/advisories/GHSA-qjxf-f2mg-c6mc
https://lists.debian.org/debian-lts-announce/2026/04/msg00000.html
https://nvd.nist.gov/vuln/detail/CVE-2026-31958
1130507 https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1130507
2446765 https://bugzilla.redhat.com/show_bug.cgi?id=2446765
GHSA-qjxf-f2mg-c6mc https://github.com/advisories/GHSA-qjxf-f2mg-c6mc
RHSA-2026:10184 https://access.redhat.com/errata/RHSA-2026:10184
RHSA-2026:11454 https://access.redhat.com/errata/RHSA-2026:11454
RHSA-2026:11493 https://access.redhat.com/errata/RHSA-2026:11493
RHSA-2026:11494 https://access.redhat.com/errata/RHSA-2026:11494
RHSA-2026:11495 https://access.redhat.com/errata/RHSA-2026:11495
RHSA-2026:8093 https://access.redhat.com/errata/RHSA-2026:8093
USN-8198-1 https://usn.ubuntu.com/8198-1/
USN-8198-2 https://usn.ubuntu.com/8198-2/
No exploits are available.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L Found at https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2026-31958.json
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

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local

physical

low

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none

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required

unchanged

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none
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

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Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://github.com/tornadoweb/tornado
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

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none

low

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none

required

unchanged

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none
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N Found at https://github.com/tornadoweb/tornado
Attack Vector (AV) Attack Complexity (AC) Attack Requirements (AT) Privileges Required (PR) User Interaction (UI) Vulnerable System Impact Confidentiality (VC) Vulnerable System Impact Integrity (VI) Vulnerable System Impact Availability (VA) Subsequent System Impact Confidentiality (SC) Subsequent System Impact Integrity (SI) Subsequent System Impact Availability (SA)

network

adjacent

local

physical

low

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present

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passive

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Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://github.com/tornadoweb/tornado/commit/119a195e290c43ad2d63a2cf012c29d43d6ed839
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N Found at https://github.com/tornadoweb/tornado/commit/119a195e290c43ad2d63a2cf012c29d43d6ed839
Attack Vector (AV) Attack Complexity (AC) Attack Requirements (AT) Privileges Required (PR) User Interaction (UI) Vulnerable System Impact Confidentiality (VC) Vulnerable System Impact Integrity (VI) Vulnerable System Impact Availability (VA) Subsequent System Impact Confidentiality (SC) Subsequent System Impact Integrity (SI) Subsequent System Impact Availability (SA)

network

adjacent

local

physical

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Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://github.com/tornadoweb/tornado/releases/tag/v6.5.5
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

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none

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Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N Found at https://github.com/tornadoweb/tornado/releases/tag/v6.5.5
Attack Vector (AV) Attack Complexity (AC) Attack Requirements (AT) Privileges Required (PR) User Interaction (UI) Vulnerable System Impact Confidentiality (VC) Vulnerable System Impact Integrity (VI) Vulnerable System Impact Availability (VA) Subsequent System Impact Confidentiality (SC) Subsequent System Impact Integrity (SI) Subsequent System Impact Availability (SA)

network

adjacent

local

physical

low

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none

present

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passive

active

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none

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Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://github.com/tornadoweb/tornado/security/advisories/GHSA-qjxf-f2mg-c6mc
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N Found at https://github.com/tornadoweb/tornado/security/advisories/GHSA-qjxf-f2mg-c6mc
Attack Vector (AV) Attack Complexity (AC) Attack Requirements (AT) Privileges Required (PR) User Interaction (UI) Vulnerable System Impact Confidentiality (VC) Vulnerable System Impact Integrity (VI) Vulnerable System Impact Availability (VA) Subsequent System Impact Confidentiality (SC) Subsequent System Impact Integrity (SI) Subsequent System Impact Availability (SA)

network

adjacent

local

physical

low

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present

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passive

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Vector: SSVCv2/E:N/A:Y/T:P/P:M/B:A/M:M/D:T/2026-03-12T19:55:43Z/ Found at https://github.com/tornadoweb/tornado/security/advisories/GHSA-qjxf-f2mg-c6mc
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://lists.debian.org/debian-lts-announce/2026/04/msg00000.html
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

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high

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Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N Found at https://lists.debian.org/debian-lts-announce/2026/04/msg00000.html
Attack Vector (AV) Attack Complexity (AC) Attack Requirements (AT) Privileges Required (PR) User Interaction (UI) Vulnerable System Impact Confidentiality (VC) Vulnerable System Impact Integrity (VI) Vulnerable System Impact Availability (VA) Subsequent System Impact Confidentiality (SC) Subsequent System Impact Integrity (SI) Subsequent System Impact Availability (SA)

network

adjacent

local

physical

low

high

none

present

none

low

high

none

passive

active

high

low

none

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none

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none

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Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://nvd.nist.gov/vuln/detail/CVE-2026-31958
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N Found at https://nvd.nist.gov/vuln/detail/CVE-2026-31958
Attack Vector (AV) Attack Complexity (AC) Attack Requirements (AT) Privileges Required (PR) User Interaction (UI) Vulnerable System Impact Confidentiality (VC) Vulnerable System Impact Integrity (VI) Vulnerable System Impact Availability (VA) Subsequent System Impact Confidentiality (SC) Subsequent System Impact Integrity (SI) Subsequent System Impact Availability (SA)

network

adjacent

local

physical

low

high

none

present

none

low

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none

passive

active

high

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none

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Exploit Prediction Scoring System (EPSS)
Percentile 0.08419
EPSS Score 0.0003
Published At April 2, 2026, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2026-04-01T12:53:30.534130+00:00 GithubOSV Importer Import https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/03/GHSA-qjxf-f2mg-c6mc/GHSA-qjxf-f2mg-c6mc.json 38.0.0