---
id: CVE-2026-53503
title: Thumbor is an open-source photo thumbnail service by globo.com
summary: >-
  Thumbor is an open-source photo thumbnail service by globo.com. Prior to
  7.8.0, Thumbor's filters:convolution(<matrix>, <columns>, <should_normalize>)
  filter passes the user-controlled <columns> value to a C extension
  (thumbor/ext/filter…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-20
  - CWE-369
vendor: thumbor
product: thumbor
affected:
  - thumbor <= 7.7.7
patched:
  - thumbor 7.8.0
published: '2026-07-31'
updated: '2026-09-08'
sourceUpdated: '2026-09-08T20:51:43.490'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-53503'
references:
  - url: >-
      https://github.com/thumbor/thumbor/commit/447e192e3fb92e64c12e5354a56a4a7133f69d73
    label: security-advisories@github.com
  - url: 'https://github.com/thumbor/thumbor/releases/tag/7.8.0'
    label: security-advisories@github.com
  - url: 'https://github.com/thumbor/thumbor/security/advisories/GHSA-cqjp-jf4r-h5q9'
    label: security-advisories@github.com
  - url: 'https://github.com/thumbor/thumbor/security/advisories/GHSA-cqjp-jf4r-h5q9'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - url: 'https://github.com/advisories/GHSA-cqjp-jf4r-h5q9'
tags:
  - nvd
  - ghsa
  - pip
epss: 0.00412
epssPercentile: 0.35217
aliases:
  - GHSA-cqjp-jf4r-h5q9
ecosystem: pip
ingestedAt: '2026-07-31T19:01:36.544Z'
---

## Overview

Thumbor is an open-source photo thumbnail service by globo.com. Prior to 7.8.0, Thumbor's filters:convolution(<matrix>, <columns>, <should_normalize>) filter passes the user-controlled <columns> value to a C extension (thumbor/ext/filters/_convolution.c) where it is used as a divisor (for % and /) without validating columns > 0. When columns=0, the C code triggers undefined behavior; on x86_64 this reliably results in a fatal divide-by-zero trap (SIGFPE) and crashes the Thumbor process, causing a remote denial of service. This issue is fixed in 7.8.0.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-53503)

Affected packages:

- `thumbor <= 7.7.7`

Patched in:

- `thumbor 7.8.0`

Source: https://github.com/advisories/GHSA-cqjp-jf4r-h5q9