CVE-2026-53503

HIGHPre-NVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4%, top 65% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Elevated
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.5Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Thumbor is an open-source photo thumbnail service by globo.com. Prior to 7.8.0, Thumbor's filters:convolution(, , ) filter passes the user-controlled 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.

CVSS v3
7.5
EG Score
7.5(medium)
EG Risk
65(Attend)
EG Risk 65/100SSVC: Attend

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity75% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
0%
EPSS %ILE
35%
KEV
Not listed

Published

July 31, 2026

Last Modified

July 31, 2026

Advisory Details (3)

Auto-updated Jul 31, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github_release, github.
github Patch Available🟡 PoC Available

Thumbor convolution filter allows divide-by-zero in C extension leading to remote DoS · Advisory · thumbor/thumbor · GitHub

https://github.com/thumbor/thumbor/security/advisories/GHSA-cqjp-jf4r-h5q9
github_release Patch Available

Release 7.8.0

Patch available: thumbor/thumbor 7.8.0

https://github.com/thumbor/thumbor/releases/tag/7.8.0
github_commit Patch Available

commit 447e192e3fb9 (thumbor/thumbor)

Patch available: thumbor/thumbor 7.8.0 (contains commit 447e192e3fb9)

https://github.com/thumbor/thumbor/commit/447e192e3fb92e64c12e5354a56a4a7133f69d73

Vendor Advisories for CVE-2026-53503(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(2 across 2 ecosystems)
Debian:14(1)
PackageVulnerable rangeFixed inDependents
thumbor6.3.2-3 ... 7.7.7-6 (16 versions)7.8.0-1—
PyPI(1)
PackageVulnerable rangeFixed inDependents
thumbor4.1.3 ... 7.7.7 (118 versions)7.8.0—

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 14× in last 7d / 39× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-08-19 19:06 UTCEG score recompute
  2. 2026-08-19 17:04 UTCEPSS rescore
  3. 2026-08-18 15:50 UTCEG score recompute
  4. 2026-08-18 13:48 UTCEPSS rescore
  5. 2026-08-18 01:00 UTCEG score recompute
  6. 2026-08-17 13:47 UTCEPSS rescore
  7. 2026-08-16 23:19 UTCEG score recompute
  8. 2026-08-16 14:56 UTCEPSS rescore
  9. 2026-08-16 10:29 UTCEG score recompute
  10. 2026-08-16 02:14 UTCEPSS rescore
  11. 2026-08-15 08:50 UTCEG score recompute
  12. 2026-08-15 01:30 UTCEPSS rescore
  13. 2026-08-14 07:11 UTCEG score recompute
  14. 2026-08-13 22:00 UTCEPSS rescore
  15. 2026-08-12 16:41 UTCEG score recompute
  16. 2026-08-12 13:51 UTCEPSS rescore
  17. 2026-08-11 15:02 UTCEG score recompute
  18. 2026-08-11 02:12 UTCEG score recompute
  19. 2026-08-11 00:00 UTCEPSS rescore
  20. 2026-08-10 00:31 UTCEG score recompute
  21. 2026-08-09 13:46 UTCEPSS rescore
  22. 2026-08-08 22:52 UTCEG score recompute
  23. 2026-08-08 16:37 UTCEPSS rescore
  24. 2026-08-07 21:13 UTCEG score recompute
  25. 2026-08-06 19:33 UTCEG score recompute
Show 14 more
  1. 2026-08-06 13:47 UTCEPSS rescore
  2. 2026-08-06 06:43 UTCEG score recompute
  3. 2026-08-05 19:17 UTCEPSS rescore
  4. 2026-08-04 16:14 UTCEG score recompute
  5. 2026-08-04 15:10 UTCEPSS rescore
  6. 2026-08-04 10:39 UTCEPSS rescore
  7. 2026-08-03 14:34 UTCEG score recompute
  8. 2026-08-03 10:36 UTCEPSS rescore
  9. 2026-08-02 12:54 UTCEG score recompute
  10. 2026-08-02 02:27 UTCEPSS rescore
  11. 2026-07-31 22:24 UTCEG score recompute
  12. 2026-07-31 22:06 UTCEG score recompute
  13. 2026-07-31 19:23 UTCEG score recompute
  14. 2026-07-31 19:07 UTCEG score recompute

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-53503?
CVE-2026-53503 is a high vulnerability published on July 31, 2026. Thumbor is an open-source photo thumbnail service by globo.com. Prior to 7.8.0, Thumbor's filters:convolution(<matrix>, <columns>, <shouldnormalize>) 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 /)…
When was CVE-2026-53503 disclosed?
CVE-2026-53503 was first published in the National Vulnerability Database on July 31, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-53503 actively exploited?
CVE-2026-53503 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 65.0% of all scored CVEs.
What is the CVSS score of CVE-2026-53503?
CVE-2026-53503 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-53503?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-53503, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-53503

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