CVE-2026-53501

HIGHPre-NVD 8.28.2—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.2 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2%, top 89% 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
8.2EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.2Exploit: None knownExposed: 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 HMAC validation can be bypassed due to the use of Python’s .replace() when removing the signature from the URL before validation. Since .replace() removes all occurrences of the substring, an attacker can insert the same signature multiple times in the URL and manipulate the final URL used for validation. This allows crafting URLs where the validated string differs from the actual requested resource, enabling loading images from unintended domains or paths. This issue is fixed in 7.8.0.

CVSS v3
8.2
EG Score
8.2(medium)
EG Risk
52(Track)
EG Risk 52/100SSVC: Track

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
Severity82% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
11%
KEV
Not listed

Published

July 31, 2026

Last Modified

July 31, 2026

Advisory Details (3)

Auto-updated Jul 31, 2026
Patch available. Sources: github_commit, github_release, github.
github Patch Available

HMAC validation bypass via multiple .replace() calls when removing URL signature · Advisory · thumbor/thumbor · GitHub

https://github.com/thumbor/thumbor/security/advisories/GHSA-mw3h-qjxj-6xg9
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 e3ae3e250053 (thumbor/thumbor)

Patch available: thumbor/thumbor 7.8.0 (contains commit e3ae3e250053)

https://github.com/thumbor/thumbor/commit/e3ae3e2500537b4d735df4144129a649374bb70b

Vendor Advisories for CVE-2026-53501(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(1)

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. 2026-08-20 22:55 UTCEPSS rescore
  2. 2026-08-19 20:26 UTCEG score recompute
  3. 2026-08-19 17:04 UTCEPSS rescore
  4. 2026-08-18 18:22 UTCEG score recompute
  5. 2026-08-18 13:48 UTCEPSS rescore
  6. 2026-08-17 16:09 UTCEG score recompute
  7. 2026-08-17 13:47 UTCEPSS rescore
  8. 2026-08-17 03:09 UTCEG score recompute
  9. 2026-08-16 14:56 UTCEPSS rescore
  10. 2026-08-16 14:08 UTCEG score recompute
  11. 2026-08-16 02:14 UTCEPSS rescore
  12. 2026-08-15 12:07 UTCEG score recompute
  13. 2026-08-15 01:30 UTCEPSS rescore
  14. 2026-08-14 10:06 UTCEG score recompute
  15. 2026-08-13 22:00 UTCEPSS rescore
  16. 2026-08-12 18:56 UTCEG score recompute
  17. 2026-08-12 13:51 UTCEPSS rescore
  18. 2026-08-11 16:54 UTCEG score recompute
  19. 2026-08-11 03:53 UTCEG score recompute
  20. 2026-08-11 00:00 UTCEPSS rescore
  21. 2026-08-10 01:52 UTCEG score recompute
  22. 2026-08-09 13:46 UTCEPSS rescore
  23. 2026-08-08 23:51 UTCEG score recompute
  24. 2026-08-08 16:37 UTCEPSS rescore
  25. 2026-08-07 21:49 UTCEG score recompute
Show 14 more
  1. 2026-08-06 19:47 UTCEG score recompute
  2. 2026-08-06 13:47 UTCEPSS rescore
  3. 2026-08-06 06:47 UTCEG score recompute
  4. 2026-08-05 19:17 UTCEPSS rescore
  5. 2026-08-04 15:26 UTCEG score recompute
  6. 2026-08-04 15:10 UTCEPSS rescore
  7. 2026-08-04 10:39 UTCEPSS rescore
  8. 2026-08-03 13:26 UTCEG score recompute
  9. 2026-08-03 10:36 UTCEPSS rescore
  10. 2026-08-02 11:25 UTCEG score recompute
  11. 2026-08-02 02:27 UTCEPSS rescore
  12. 2026-07-31 20:22 UTCEG score recompute
  13. 2026-07-31 19:23 UTCEG score recompute
  14. 2026-07-31 19:07 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-53501?
CVE-2026-53501 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 HMAC validation can be bypassed due to the use of Python’s .replace() when removing the signature from the URL before validation. Since .replace() removes all occurrences of the substring, an attacker can…
When was CVE-2026-53501 disclosed?
CVE-2026-53501 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-2026-53501 actively exploited?
CVE-2026-53501 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 88.7% of all scored CVEs.
What is the CVSS score of CVE-2026-53501?
CVE-2026-53501 has a CVSS v3 base score of 8.2 (NVD).
How do I remediate CVE-2026-53501?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-53501, 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

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