CVE-2026-104721

MEDIUMPre-NVD 6.36.3—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3% (24th 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
Trending — 4 sources updated this week
6.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 6.3Exploit: None knownExposed services: Not assessed

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

Path-traversal vulnerability in QOS.CH Sarl Logback-classic on Java (logback-classic module) allows path-traversal vulnerability. More specifically, an MDC-based discriminator value flows unsanitized into a nested FileAppender path, letting an attacker who influences that MDC value (e.g. via an HTTP header) create and append log files outside the intended directory.

This issue affects Logback-classic: from 0.9.14 through 1.6.4.  This vulnerability is similar to CVE-2026-19880 but involves other attack techniques.

CVSS v3
6.3
EG Score
6.3MEDIUMmedium confidence
EG Risk
33
EG Risk 33/100CISA 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
Severity63% × 45%
Exploitation0% × 40%
Automatability30% × 15%
CISA SSVC: Track at low or medium mission impact; Track or Attend at high (mission-essential systems).
Action: No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.
EPSS PROB
0.3%
EPSS %ILE
24th
KEV
Not listed

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

No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.

Exploitation none (no KEV listing, exploit record or EPSS ≥ 50%) · Automatable unknown (not published for this CVE) · Technical impact partial (CVSS below 9.0). 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

October 2, 2026

Last Modified

October 2, 2026

Advisory Details (1)

Auto-updated Oct 2, 2026
No patch confirmed yet.
generic

News

https://logback.qos.ch/news.html#1.6.5

Vendor Advisories for CVE-2026-104721(1)

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

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 8× 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. 2026-10-03 18:26 UTCEG score recompute
  2. 2026-10-03 18:25 UTCGHSA enrichment
  3. 2026-10-03 14:25 UTCEPSS rescore
  4. 2026-10-02 18:15 UTCGHSA enrichment
  5. 2026-10-02 18:14 UTCGHSA enrichment
  6. 2026-10-02 14:22 UTCEG score recompute
  7. 2026-10-02 13:26 UTCEG score recompute
  8. 2026-10-02 13:25 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-104721?
CVE-2026-104721 is a medium vulnerability published on October 2, 2026. Path-traversal vulnerability in QOS.CH Sarl Logback-classic on Java (logback-classic module) allows path-traversal vulnerability. More specifically, an MDC-based discriminator value flows unsanitized into a nested FileAppender path, letting an attacker who influences that MDC value (e.g. via an…
When was CVE-2026-104721 disclosed?
CVE-2026-104721 was first published on October 2, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-104721 actively exploited?
CVE-2026-104721 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (24th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-104721?
CVE-2026-104721 has a CVSS base score of 6.3 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-104721?
No fix for CVE-2026-104721 is confirmed yet. Until one is published, restrict network exposure of the affected system or apply the vendor's mitigation — for example, keep it off the internet or limit it to trusted networks — and watch the vendor's advisory for the fix. The vendor advisories EchelonGraph has for CVE-2026-104721 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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