CVE-2021-21735

MEDIUMNVD 6.56.5—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.5 under NVD CVSS v3. EPSS exploit probability: 0.9%, top 43% 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, nvd
Elevated
6.5
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 1%CVSS: 6.5Exploit: NoneExposed: 0

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

A ZTE product has an information leak vulnerability. Due to improper permission settings, an attacker with ordinary user permissions could exploit this vulnerability to obtain some sensitive user information through the wizard page without authentication. This affects ZXHN H168N all versions up to V3.5.0_EG1T4_TE.

CVSS v3
6.5
EG Score
6.5(medium)
EG Risk
50(Track)
EG Risk 50/100SSVC: 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
Severity65% × 45%
Exploitation40% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
56.8%
KEV
Not listed

Published

June 10, 2021

Last Modified

May 26, 2026

References (3)

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 10× 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.

  1. 2026-07-23 01:57 UTCEG score recompute
  2. 2026-07-22 22:43 UTCEG score recompute
  3. 2026-07-22 14:05 UTCEPSS rescore
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  69. 2026-05-26 15:08 UTCGHSA enrichment
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Publicly available exploits

(1 reference)

Working exploit code is in the public domain (1 GitHub PoC). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • GitHub PoCminanagehsalalma/cve-2021-21735-zte-zxhn-h168n-admin-compromise
    First seen May 19, 2026

    CVE-2021-21735 write-up: ZTE ZXHN H168N V3.5 wizard-page information leak, firmware routing flaw, and the path from exposed PPPoE/WLAN data to full admin compromise.

    Open source ↗

Frequently asked(5)

What is CVE-2021-21735?
CVE-2021-21735 is a medium vulnerability published on June 10, 2021. A ZTE product has an information leak vulnerability. Due to improper permission settings, an attacker with ordinary user permissions could exploit this vulnerability to obtain some sensitive user information through the wizard page without authentication. This affects ZXHN H168N all versions up to…
When was CVE-2021-21735 disclosed?
CVE-2021-21735 was first published in the National Vulnerability Database on June 10, 2021, with the most recent update on May 26, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-21735 actively exploited?
CVE-2021-21735 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 56.8% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-21735?
CVE-2021-21735 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2021-21735?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-21735, 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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