CVE-2026-53503Public exploitNetwork attack vector

Process crash via zero convolution columns

Published Jul 31, 2026 · Updated Jul 31, 2026

Divide-by-zero in thumbor before 7.8.0 allows remote attackers to crash the server through a crafted convolution-filter URL. The filter accepts columns=0 and passes it to _convolution.c, which uses the value in modulo and division operations without a zero check, triggering SIGFPE on x86_64. The default convolution filter is reachable without authentication when unsafe URLs are enabled; otherwise, a valid signed URL is required, and the process crash interrupts service.

CVSS severity7.5
High
EPSS probability0.41%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Divide-by-zero in thumbor before 7.8.0 allows remote attackers to crash the server through a crafted convolution-filter URL. The filter accepts columns=0 and passes it to _convolution.c, which uses the value in modulo and division operations without a zero check, triggering SIGFPE on x86_64. The default convolution filter is reachable without authentication when unsafe URLs are enabled; otherwise, a valid signed URL is required, and the process crash interrupts service.

The record

CVE
CVE-2026-53503
Published
Jul 31, 2026
Updated
Jul 31, 2026
Vendor
thumbor
Product
thumbor
Classifications
CWE-369, CWE-20, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 31, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 31, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 7.8.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

thumbor · thumborversion=< 7.8.0

Published CVSS scores

7.5GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-369Divide By Zero
CWE-20Improper Input Validation
T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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