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Response snapshot Nov 5, 2026, 23:11 UTC

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VulnerabilityCVE-2026-104269

ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx.

ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. From 3.0.0 until 3.0.17, ModSecurity's multipart parser does not apply the RFC 2231 filename* parameter precedence used by common Go, Python, Node.js, and Java application parsers.

At a glance

Exploited
Not known
Severity
8.6 High (CVSS 3.1)
Chance of exploitation
Not estimated
Sources
1 source

What to do

Check the vendor advisory for affected versions and fixes.

Read NVD CVE-2026-104269 (opens a new tab)

What happened

ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. From 3.0.0 until 3.0.17, ModSecurity's multipart parser does not apply the RFC 2231 filename* parameter precedence used by common Go, Python, Node.js, and Java application parsers.

A Content-Disposition header can provide a benign filename parameter for ModSecurity and a different encoded filename* value that the backend prefers, causing MULTIPART_FILENAME rules and the application to make security decisions on different names. Applications that use the backend-selected name for storage, extension checks, or content-type inference can therefore receive a filename that bypassed WAF inspection.

PHP's native multipart parser is not affected by this discrepancy. This issue is fixed in version 3.0.17.

Scores and how they were measured

CVSS base severity

8.6

Version 3.1As of

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

Not available

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Related technology

Sources

  1. Primary source

    NVD CVE-2026-104269 (opens a new tab)

    NVD record: description, CVSS (the CNA score is preferred), affected products, and publication date. Not evidence of exploitation.

    Published Checked

  2. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  3. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  4. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, November 5). ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. (CVE-2026-104269). https://kevwire.com/record/CVE-2026-104269

MLA

"ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. (CVE-2026-104269)." KEVWire, 5 Nov. 2026, kevwire.com/record/CVE-2026-104269.

Chicago

KEVWire. "ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. (CVE-2026-104269)." Last modified November 5, 2026. https://kevwire.com/record/CVE-2026-104269.

Evidence summary (plain text)

ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. (Nov 5, 2026).
ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. From 3.0.0 until 3.0.17, ModSecurity's multipart parser does not apply the RFC 2231 filename* parameter precedence used by common Go, Python, Node.js, and Java application parsers. A Content-Disposition header can provide a benign filename parameter for ModSecurity and a different encoded filename* value that the backend prefers, causing MULTIPART_FILENAME rules and the application to make security decisions on different names.
CVSS 8.6 (version 3.1; evidence as of Nov 5, 2026; https://nvd.nist.gov/vuln/detail/CVE-2026-104269).
Sources:
NVD CVE-2026-104269: https://nvd.nist.gov/vuln/detail/CVE-2026-104269
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-05T16:06:14.984Z&lastModEndDate=2026-11-05T17:35:56.143Z&resultsPerPage=500&startIndex=500
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-05T15:36:26.668Z&lastModEndDate=2026-11-05T17:05:56.758Z&resultsPerPage=500&startIndex=0
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-05T15:01:02.006Z&lastModEndDate=2026-11-05T16:35:57.513Z&resultsPerPage=500&startIndex=500
Record ID: CVE-2026-104269.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Nov 5, 2026, 17:35 UTC. Ingestion is not an independent editorial investigation.

NVD status: Received. Publication in the NVD is not evidence of exploitation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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Record details

Record detail