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Response snapshot Nov 6, 2026, 19:41 UTC

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VulnerabilityCVE-2026-118515

The Symfony Serializer component DataUriNormalizer handles only the exact types SplFileInfo, SplFileObject, and File, so for a property typed with a subclass such as UploadedFile,...

The Symfony Serializer component DataUriNormalizer handles only the exact types SplFileInfo, SplFileObject, and File, so for a property typed with a subclass such as UploadedFile, ObjectNormalizer instantiates the object through its constructor from attacker-controlled data, including the file path.

At a glance

Exploited
Not known
Severity
8.4 High (CVSS 4.0)
Chance of exploitation
Not estimated
Sources
1 source

What to do

Check the vendor advisory for affected versions and fixes.

Read NVD CVE-2026-118515 (opens a new tab)

What happened

The Symfony Serializer component DataUriNormalizer handles only the exact types SplFileInfo, SplFileObject, and File, so for a property typed with a subclass such as UploadedFile, ObjectNormalizer instantiates the object through its constructor from attacker-controlled data, including the file path. This allows an arbitrary file on the server to be treated as an uploaded file in Symfony versions prior to 5.4.56, 6.

x prior to 6.4.50, 7.x prior to 7.4.23, and 8.x prior to 8.1.11.

A request body such as {"image": {"path": "/path/to/project/.env.local", "originalName": "a.png", "test": true}} makes the application handle any file on the server as an upload, without the file being sent. With test: true, UploadedFile::isValid() skips is_uploaded_file() and move() falls back to rename().

Assert\File does not prevent this because it validates the file at the attacker-chosen path, which exists on the server. Any code that deserializes untrusted data into a type that holds such a property is affected. That includes #[MapRequestPayload] on a DTO with an UploadedFile property, which is how uploads are mapped in Symfony 8.1; a single unauthenticated request with a JSON or form body is enough.

Continue reading

Depending on what the application does with the upload, this can expose any file readable by PHP (for instance, when uploads are stored and served back), move any such file when move() is called, and reveal whether a path exists.

A serializer built without DataUriNormalizer ahead of the object normalizer is not protected by the fix; the serializer configured by FrameworkBundle is.

Scores and how they were measured

CVSS base severity

8.4

Version 4.0As of

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:L/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

Not available

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

Sources

  1. Primary source

    NVD CVE-2026-118515 (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 6). The Symfony Serializer component DataUriNormalizer handles only the exact types SplFileInfo, SplFileObject, and File, so for a property typed with a subclass such as UploadedFile,... (CVE-2026-118515). https://kevwire.com/record/CVE-2026-118515

MLA

"The Symfony Serializer component DataUriNormalizer handles only the exact types SplFileInfo, SplFileObject, and File, so for a property typed with a subclass such as UploadedFile,... (CVE-2026-118515)." KEVWire, 6 Nov. 2026, kevwire.com/record/CVE-2026-118515.

Chicago

KEVWire. "The Symfony Serializer component DataUriNormalizer handles only the exact types SplFileInfo, SplFileObject, and File, so for a property typed with a subclass such as UploadedFile,... (CVE-2026-118515)." Last modified November 6, 2026. https://kevwire.com/record/CVE-2026-118515.

Evidence summary (plain text)

The Symfony Serializer component DataUriNormalizer handles only the exact types SplFileInfo, SplFileObject, and File, so for a property typed with a subclass such as UploadedFile,... (Nov 6, 2026).
The Symfony Serializer component DataUriNormalizer handles only the exact types SplFileInfo, SplFileObject, and File, so for a property typed with a subclass such as UploadedFile, ObjectNormalizer instantiates the object through its constructor from attacker-controlled data, including the file path. This allows an arbitrary file on the server to be treated as an uploaded file in Symfony versions prior to 5.4.56, 6.x prior to 6.4.50, 7.x prior to 7.4.23, and 8.x prior to 8.1.11.
CVSS 8.4 (version 4.0; evidence as of Nov 6, 2026; https://nvd.nist.gov/vuln/detail/CVE-2026-118515).
Sources:
NVD CVE-2026-118515: https://nvd.nist.gov/vuln/detail/CVE-2026-118515
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-06T17:06:05.906Z&lastModEndDate=2026-11-06T18:35:59.598Z&resultsPerPage=500&startIndex=500
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-06T16:31:13.932Z&lastModEndDate=2026-11-06T18:05:57.615Z&resultsPerPage=500&startIndex=500
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-06T15:50:58.372Z&lastModEndDate=2026-11-06T17:30:57.197Z&resultsPerPage=500&startIndex=1000
Record ID: CVE-2026-118515.
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 6, 2026, 18:35 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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