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: 0.4% (26th percentile of EPSS-scored CVEs). 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: 0.4%CVSS: 8.2Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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
8.2HIGHmedium confidence
EG Risk
52
EG Risk 52/100CISA SSVC

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%
CISA SSVC: Track at low or medium mission impact; Attend at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.4%
EPSS %ILE
26th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

July 31, 2026

Last Modified

September 8, 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 rangeFix by version rangeDependents
thumbor6.3.2-3 ... 7.7.7-6 (16 versions)
  • every version up to 7.8.0-1: fixed in 7.8.0-1
—
PyPI(1)
PackageVulnerable rangeFix by version rangeDependents
thumbor4.1.3 ... 7.7.7 (118 versions)
  • every version up to 7.8.0: fixed in 7.8.0
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 11× in last 7d / 46× 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.

Showing the most recent 100 of 110 total refreshes for this CVE.

  1. 2026-10-04 23:50 UTCEG score recompute
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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 on July 31, 2026, with the most recent update on September 8, 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 0.4% probability of exploitation in the next 30 days (26th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-53501?
CVE-2026-53501 has a CVSS base score of 8.2 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-53501?
A fix for CVE-2026-53501 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-53501 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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