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Response snapshot Oct 27, 2026, 06:21 UTC

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VulnerabilityCVE-2026-15176

A vulnerability exists in NGINX Plus and NGINX Open Source when a location is configured that uses the alias directive together with rewrite and a set or return directive...

A vulnerability exists in NGINX Plus and NGINX Open Source when a location is configured that uses the alias directive together with rewrite and a set or return directive referencing the $request_filename variable.

At a glance

Exploited
Not known
Severity
9.2 Critical (CVSS 4.0)
Chance of exploitation
0.8% in the next 30 days
Sources
1 source

What to do

Check the vendor advisory for affected versions and fixes.

Read NVD CVE-2026-15176 (opens a new tab)

What happened

A vulnerability exists in NGINX Plus and NGINX Open Source when a location is configured that uses the alias directive together with rewrite and a set or return directive referencing the $request_filename variable. Alternatively, the same result could be achieved when the $request_filename variable is used in an access log format directive.

An unauthenticated attacker along with conditions beyond their control can exploit this vulnerability by sending crafted HTTP requests. This may cause a heap buffer overflow in the NGINX worker process leading to a restart. Additionally, attackers can execute code on systems with Address Space Layout Randomization (ASLR) disabled or when the attacker can bypass ASLR.

Impact: This vulnerability may allow remote attackers to cause a denial-of-service (DoS) on the NGINX system or to possibly trigger a code execution. There is no control plane exposure; this is a data plane issue only.

Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Scores and how they were measured

CVSS base severity

9.2

Version 4.0As of

CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Measurement source (opens a new tab)

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

EPSS probability

0.8%

Scored Percentile 57.7%

Model and measurement source (opens a new tab)

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

Sources

  1. Primary source

    NVD CVE-2026-15176 (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

    FIRST measured EPSS score (opens a new tab)

    Measured EPSS probability and percentile for CVE-2026-15176, scored 2026-10-26. A model estimate, not proof of exposure.

    Published Checked

Cite this record

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

APA

KEVWire. (2026, October 15). A vulnerability exists in NGINX Plus and NGINX Open Source when a location is configured that uses the alias directive together with rewrite and a set or return directive... (CVE-2026-15176). https://kevwire.com/record/CVE-2026-15176

MLA

"A vulnerability exists in NGINX Plus and NGINX Open Source when a location is configured that uses the alias directive together with rewrite and a set or return directive... (CVE-2026-15176)." KEVWire, 15 Oct. 2026, kevwire.com/record/CVE-2026-15176.

Chicago

KEVWire. "A vulnerability exists in NGINX Plus and NGINX Open Source when a location is configured that uses the alias directive together with rewrite and a set or return directive... (CVE-2026-15176)." Last modified October 15, 2026. https://kevwire.com/record/CVE-2026-15176.

Evidence summary (plain text)

A vulnerability exists in NGINX Plus and NGINX Open Source when a location is configured that uses the alias directive together with rewrite and a set or return directive... (Oct 14, 2026).
A vulnerability exists in NGINX Plus and NGINX Open Source when a location is configured that uses the alias directive together with rewrite and a set or return directive referencing the $request_filename variable. Alternatively, the same result could be achieved when the $request_filename variable is used in an access log format directive. An unauthenticated attacker along with conditions beyond their control can exploit this vulnerability by sending crafted HTTP requests. This may cause a heap buffer overflow in the NGINX worker process leading to a restart. Additionally, attackers can execute code on systems with Address Space Layout Randomization (ASLR) disabled or when the attacker can bypass ASLR.

Impact:
This vulnerability may allow remote attackers to cause a denial-of-service (DoS) on the NGINX system or to possibly trigger a code execution. There is no control plane exposure; this is a data plane issue only.




Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
CVSS 9.2 (version 4.0; evidence as of Oct 15, 2026; https://nvd.nist.gov/vuln/detail/CVE-2026-15176).
EPSS 0.8% for the following 30 days, scored Oct 26, 2026 (https://api.first.org/data/v1/epss?cve=CVE-2026-15176&date=2026-10-26).
Sources:
NVD CVE-2026-15176: https://nvd.nist.gov/vuln/detail/CVE-2026-15176
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2026-15176
FIRST measured EPSS score: https://api.first.org/data/v1/epss?cve=CVE-2026-15176&date=2026-10-26
Record ID: CVE-2026-15176.
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: Oct 27, 2026, 03:52 UTC. Ingestion is not an independent editorial investigation.

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

Looked up on demand from NVD because this CVE is outside the regularly tracked set (older, or rated below HIGH). It is not in CISA's Known Exploited Vulnerabilities catalog as of the last ingestion.

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.

Record JSON

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Record details

Record detail