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Response snapshot Oct 28, 2026, 02:46 UTC

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VulnerabilityCVE-2026-5821

The Image Optimizer plugin for WordPress is vulnerable to arbitrary file deletion in versions up to and including 1.7.4.

The Image Optimizer plugin for WordPress is vulnerable to arbitrary file deletion in versions up to and including 1.7.4.

At a glance

Exploited
Not known
Severity
8.1 High (CVSS 3.1)
Chance of exploitation
0.7% in the next 30 days
Sources
1 source

What to do

Check the vendor advisory for affected versions and fixes.

Read NVD CVE-2026-5821 (opens a new tab)

What happened

The Image Optimizer plugin for WordPress is vulnerable to arbitrary file deletion in versions up to and including 1.7.4. This is due to insufficient path validation in the Image_Backup::remove() function where backup file paths stored in post meta are used directly in file deletion operations without verifying they are within the uploads directory.

The plugin stores backup file paths in the image_optimizer_metadata post meta field and trusts these paths completely when deleting backups on the delete_attachment hook. An authenticated attacker with Author-level access can edit the image_optimizer_metadata post meta on their own attachments via WordPress's Custom Fields interface, injecting arbitrary absolute file paths into the backups array.

When the attacker subsequently deletes the attachment, the plugin calls File_System::delete() on each path without validation. This makes it possible for authenticated attackers, with Author-level access and above, to delete arbitrary files on the server within the web server's filesystem permissions, potentially leading to denial of service, data loss, or security degradation.

Scores and how they were measured

CVSS base severity

8.1

Version 3.1As of

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

Measurement source (opens a new tab)

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

EPSS probability

0.7%

Scored Percentile 51.4%

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.

Related technology

Sources

  1. Primary source

    NVD CVE-2026-5821 (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

  5. Primary source

    FIRST measured EPSS score (opens a new tab)

    Measured EPSS probability and percentile for CVE-2026-5821, scored 2026-10-27. This is 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 28). The Image Optimizer plugin for WordPress is vulnerable to arbitrary file deletion in versions up to and including 1.7.4. (CVE-2026-5821). https://kevwire.com/record/CVE-2026-5821

MLA

"The Image Optimizer plugin for WordPress is vulnerable to arbitrary file deletion in versions up to and including 1.7.4. (CVE-2026-5821)." KEVWire, 28 Oct. 2026, kevwire.com/record/CVE-2026-5821.

Chicago

KEVWire. "The Image Optimizer plugin for WordPress is vulnerable to arbitrary file deletion in versions up to and including 1.7.4. (CVE-2026-5821)." Last modified October 28, 2026. https://kevwire.com/record/CVE-2026-5821.

Evidence summary (plain text)

The Image Optimizer plugin for WordPress is vulnerable to arbitrary file deletion in versions up to and including 1.7.4. (Jul 2, 2026).
The Image Optimizer plugin for WordPress is vulnerable to arbitrary file deletion in versions up to and including 1.7.4. This is due to insufficient path validation in the Image_Backup::remove() function where backup file paths stored in post meta are used directly in file deletion operations without verifying they are within the uploads directory. The plugin stores backup file paths in the image_optimizer_metadata post meta field and trusts these paths completely when deleting backups on the delete_attachment hook.
CVSS 8.1 (version 3.1; evidence as of Oct 28, 2026; https://nvd.nist.gov/vuln/detail/CVE-2026-5821).
EPSS 0.7% for the following 30 days, scored Oct 27, 2026 (https://api.first.org/data/v1/epss?cve=CVE-2026-5821&date=2026-10-27).
Sources:
NVD CVE-2026-5821: https://nvd.nist.gov/vuln/detail/CVE-2026-5821
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-28T01:10:57.689Z&lastModEndDate=2026-10-28T02:40:57.490Z&resultsPerPage=500&startIndex=0
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-28T00:35:57.457Z&lastModEndDate=2026-10-28T02:10:57.168Z&resultsPerPage=500&startIndex=0
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-28T00:06:00.935Z&lastModEndDate=2026-10-28T01:35:55.761Z&resultsPerPage=500&startIndex=0
FIRST measured EPSS score: https://api.first.org/data/v1/epss?cve=CVE-2026-5821&date=2026-10-27
Record ID: CVE-2026-5821.
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 28, 2026, 01:51 UTC. Ingestion is not an independent editorial investigation.

NVD status: Deferred. 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.

Record JSON

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Record details

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