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CVE Record

CVE-2026-27784: NGINX ngx_http_mp4_module vulnerability

The 32-bit implementation of NGINX Open Source has a vulnerability in the ngx_http_mp4_module module, which might allow an attacker to over-read or over-write NGINX worker memory resulting in its termination, using a specially crafted MP4 file. The issue only affects 32-bit NGINX Open Source if it is built with the ngx_http_mp4_module module and the mp4 directive is used in the configuration file. Additionally, the attack is possible only if an attacker can trigger the processing of a specially crafted MP4 file with the ngx_http_mp4_module module. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

HighCVSS 8.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

This issue affects a narrow NGINX Open Source setup: 32-bit builds using the MP4 module with the mp4 directive enabled. A crafted MP4 can corrupt or over-read worker memory and terminate a worker. Business risk is highest for sites that process or serve untrusted MP4 files through affected NGINX configurations.

Executive priority

Prioritize verification for media-serving environments and legacy 32-bit systems. The affected configuration is specific, but impact is high where present because crafted media can affect NGINX worker memory and availability. Treat remediation as urgent for internet-facing or user-uploaded MP4 workflows.

Technical view

CVE-2026-27784 is a CWE-190 integer overflow in the 32-bit implementation of ngx_http_mp4_module. Exploitation requires an attacker to trigger processing of a specially crafted MP4 file by the module. The CVSS 4.0 score is 8.5, with high confidentiality, integrity, and availability impact stated in the record.

Likely exposure

Exposure appears limited to 32-bit NGINX Open Source builds compiled with ngx_http_mp4_module, with the mp4 directive enabled, and reachable MP4 processing paths. 64-bit builds or configurations not using the module are not described as affected in the provided sources.

Exploitation context

The bundle does not cite active exploitation, and KEV is false. Sources describe a crafted MP4 triggering worker memory over-read or over-write, potentially terminating the worker. The record’s CVSS vector indicates local access and low privileges, but operational exposure depends on how MP4 files reach NGINX.

Researcher notes

Do not generalize this to all NGINX deployments. The provided scope requires 32-bit NGINX Open Source, ngx_http_mp4_module, the mp4 directive, and attacker-triggered MP4 processing. Evidence in the bundle does not establish public exploitation or affected end-of-technical-support versions.

Mitigation direction

  • Check F5 and Red Hat advisories for applicable fixed packages or vendor guidance.
  • Disable the mp4 directive where MP4 pseudo-streaming is not required.
  • Avoid affected 32-bit NGINX Open Source builds where feasible.
  • Restrict untrusted MP4 upload or processing paths until remediation is confirmed.
  • Monitor NGINX worker crashes and abnormal MP4 request patterns.

Validation and detection

  • Inventory NGINX Open Source deployments and confirm whether any are 32-bit builds.
  • Review NGINX build options for ngx_http_mp4_module presence.
  • Review configuration for active mp4 directives.
  • Map whether external users can cause MP4 files to be processed by NGINX.
  • Compare installed packages against F5 and Red Hat advisory status.
Prepared
Confidence
high
Sources
9

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-190: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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cve · low confidence lookup

CVE-2026-27784 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
High
CVSS
8.5 (4.0)
Known Exploited
No
Published

Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

3CVSS vectors
5Timeline events
2ADP providers
20Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: total

CVSS vector scores

3 official scores

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
8.5CVSS 4.0HighCVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N——f5
7.8CVSS 3.1HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H1.85.9f5
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6redhat-SADP

Vulnerability scoring details

Base CVSS 4.0 score

8.5High
CVSS 4.0 vector shape for CVE-2026-27784Attack VectorAttack ComplexityAttack RequirementsPrivileges RequiredUser InteractionVS ConfidentialityVS IntegrityVS AvailabilitySS ConfidentialitySS IntegritySS Availability

Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Attack Requirements
NonePresent
Privileges Required
NoneLowHigh
User Interaction
NonePassiveActive
VS Confidentiality
HighLowNone
VS Integrity
HighLowNone
VS Availability
HighLowNone
SS Confidentiality
HighLowNone
SS Integrity
HighLowNone
SS Availability
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. ADP timelineredhat-SADP

    Made public.

  3. CVE publishedCVE Program

    The CVE record was published.

  4. ADP timelineredhat-SADP

    Reported to Red Hat.

  5. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
redhat-SADPNGINX: NGINX: Denial of Service due to memory corruption via crafted MP4 file
other:Red Hat severity ratingcvssV3_1
  • 2026-03-24T15:02:07.092Z: Reported to Red Hat.
  • 2026-03-24T14:13:25.343Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
F5NGINX Open Source1.29.0, 1.1.19unknown
Weakness

CWE details

CWE-190

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-190 · source CWE mapping

Integer Overflow or Wraparound

Integer Overflow or Wraparound represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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