CVE-2026-93421

MEDIUMPre-NVD 5.35.3—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4% (32nd 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
5.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 5.3Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Mesop is a Python-based UI framework that allows users to build web applications. Prior to 1.3.4, the unauthenticated /__csp__ endpoint passes attacker-controlled document-uri, blocked-uri, and violated-directive values to the csp_report handler in mesop/server/static_file_serving.py, which prints them to standard output without neutralizing terminal control sequences. When an operator views the resulting logs in an ANSI-capable terminal, injected ANSI or VT100 sequences can clear or reposition the display, hide text, or present forged messages, reducing the integrity of monitoring and incident-response output. This issue is fixed in version 1.3.4.

CVSS v3
5.3
EG Score
5.3MEDIUMmedium confidence
EG Risk
24
EG Risk 24/100CISA 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
Severity53% × 45%
Exploitation0% × 40%
Automatability0% × 15%
CISA SSVC: Track at every mission impact level.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.4%
EPSS %ILE
32nd
KEV
Not listed

CISA SSVCTrack at every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (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

September 23, 2026

Last Modified

September 30, 2026

Advisory Details (4)

Auto-updated Sep 23, 2026
🔬 Proof of concept available. Patch available. Sources: github, github_pr, github_commit, github_release.
github_release Patch Available

v1.3.4

Patch available: mesop-dev/mesop v1.3.4

https://github.com/mesop-dev/mesop/releases/tag/v1.3.4
github_commit Patch Available

commit f38c42a1d3eb (mesop-dev/mesop)

Patch available: mesop-dev/mesop v1.3.4 (contains commit f38c42a1d3eb)

https://github.com/mesop-dev/mesop/commit/f38c42a1d3eba246941ef8d7f645072d53c58785
github_pr Patch Available

Sanitize ANSI escape sequences in CSP report logging

Patch available: mesop-dev/mesop v1.3.4 (PR #1397 merged 2026-08-01)

https://github.com/mesop-dev/mesop/pull/1397
github Patch Available🟡 PoC Available

Unauthenticated ANSI Escape Sequence Injection in CSP Reporting Endpoint · Advisory · mesop-dev/mesop · GitHub

https://github.com/mesop-dev/mesop/security/advisories/GHSA-g7f6-rxc4-qhph

Vendor Advisories for CVE-2026-93421(1)

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

Affected Packages

(1 across 1 ecosystem)
PyPI(1)
PackageVulnerable rangeFix by version rangeDependents
mesop0.0.1 ... 1.3.3 (104 versions)
  • every version up to 1.3.4: fixed in 1.3.4
—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 12× in last 7d / 23× 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. 2026-10-05 01:24 UTCEG score recompute
  2. 2026-10-04 23:23 UTCEPSS rescore
  3. 2026-10-03 23:30 UTCEG score recompute
  4. 2026-10-03 14:26 UTCEPSS rescore
  5. 2026-10-02 21:36 UTCEG score recompute
  6. 2026-10-01 19:51 UTCEPSS rescore
  7. 2026-09-30 17:49 UTCEG score recompute
  8. 2026-09-30 15:04 UTCEPSS rescore
  9. 2026-09-30 07:48 UTCEG score recompute
  10. 2026-09-29 05:53 UTCEG score recompute
  11. 2026-09-28 13:52 UTCEPSS rescore
  12. 2026-09-28 13:52 UTCEPSS rescore
  13. 2026-09-28 03:59 UTCEG score recompute
  14. 2026-09-27 13:49 UTCEPSS rescore
  15. 2026-09-27 02:05 UTCEG score recompute
  16. 2026-09-26 15:59 UTCEPSS rescore
  17. 2026-09-24 22:16 UTCEG score recompute
  18. 2026-09-24 14:04 UTCEPSS rescore
  19. 2026-09-23 20:22 UTCEG score recompute
  20. 2026-09-23 19:48 UTCEG score recompute
  21. 2026-09-23 19:26 UTCEG score recompute
  22. 2026-09-23 19:04 UTCEG score recompute
  23. 2026-09-23 19:04 UTCMITRE cvelistV5first tracked

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2026-93421?
CVE-2026-93421 is a medium vulnerability published on September 23, 2026. Mesop is a Python-based UI framework that allows users to build web applications. Prior to 1.3.4, the unauthenticated /csp endpoint passes attacker-controlled document-uri, blocked-uri, and violated-directive values to the cspreport handler in mesop/server/staticfile_serving.py, which prints them…
When was CVE-2026-93421 disclosed?
CVE-2026-93421 was first published on September 23, 2026, with the most recent update on September 30, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-93421 actively exploited?
CVE-2026-93421 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (32nd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-93421?
CVE-2026-93421 has a CVSS base score of 5.3 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-93421?
A fix for CVE-2026-93421 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-93421 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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