CVE-2026-20503

MEDIUMPre-NVD 5.35.3—
EchelonGraph scoreHIGH confidence

Score 5.3 from GitHub Security Advisory published 2026-09-07. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 5.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, epss, ghsa
Trending — 3 sources updated this week
5.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.3Exploit: None knownExposed: 0

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

In Modem, there is a possible system crash due to a missing bounds check. This could lead to remote denial of service, if a UE has connected to a rogue base station controlled by the attacker, with no additional execution privileges needed. User interaction is not needed for exploitation. Patch ID: MOLY01371002; Issue ID: MSV-9020.

CVSS v3
5.3
EG Score
5.3(high)
EG Risk
24(Track)
EG Risk 24/100SSVC: 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
Severity53% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
9%
KEV
Not listed

Published

September 7, 2026

Last Modified

September 9, 2026

Advisory Details (1)

Auto-updated Sep 7, 2026
⚠️ Active exploitation confirmed. No patch confirmed yet.
generic🔴 Active Exploitation

September 2026 MediaTek Security Bulletin

https://www.mediatek.com/product-security-bulletin/September-2026

Vendor Advisories for CVE-2026-20503(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 19× in last 7d / 41× 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. 2026-09-19 23:04 UTCEG score recompute
  2. 2026-09-19 23:04 UTCGHSA enrichment
  3. 2026-09-18 23:30 UTCEG score recompute
  4. 2026-09-18 23:30 UTCGHSA enrichment
  5. 2026-09-18 19:27 UTCEPSS rescore
  6. 2026-09-17 23:56 UTCEG score recompute
  7. 2026-09-17 23:56 UTCGHSA enrichment
  8. 2026-09-16 23:29 UTCEG score recompute
  9. 2026-09-16 23:29 UTCGHSA enrichment
  10. 2026-09-16 14:07 UTCEPSS rescore
  11. 2026-09-16 05:15 UTCEPSS rescore
  12. 2026-09-15 23:55 UTCEG score recompute
  13. 2026-09-15 23:55 UTCGHSA enrichment
  14. 2026-09-15 00:21 UTCGHSA enrichment
  15. 2026-09-14 00:47 UTCEG score recompute
  16. 2026-09-14 00:47 UTCGHSA enrichment
  17. 2026-09-13 16:47 UTCEPSS rescore
  18. 2026-09-13 01:14 UTCEG score recompute
  19. 2026-09-13 01:14 UTCGHSA enrichment
  20. 2026-09-12 15:01 UTCEPSS rescore
  21. 2026-09-12 01:40 UTCEG score recompute
  22. 2026-09-12 01:40 UTCGHSA enrichment
  23. 2026-09-11 14:52 UTCEPSS rescore
  24. 2026-09-11 02:06 UTCEG score recompute
  25. 2026-09-11 02:06 UTCGHSA enrichment
Show 16 more
  1. 2026-09-10 09:34 UTCEPSS rescore
  2. 2026-09-10 02:32 UTCGHSA enrichment
  3. 2026-09-09 02:58 UTCEG score recompute
  4. 2026-09-09 02:58 UTCGHSA enrichment
  5. 2026-09-08 22:00 UTCEPSS rescore
  6. 2026-09-08 19:54 UTCGHSA enrichment
  7. 2026-09-08 10:59 UTCEG score recompute
  8. 2026-09-08 10:59 UTCGHSA enrichment
  9. 2026-09-07 16:01 UTCEPSS rescore
  10. 2026-09-07 11:23 UTCGHSA enrichment
  11. 2026-09-07 10:46 UTCEG score recompute▲ 5.30
  12. 2026-09-07 10:45 UTCGHSA enrichment
  13. 2026-09-07 10:41 UTCMITRE cvelistV5CVSS v3 → 5.3 · severity → MEDIUM
  14. 2026-09-07 02:29 UTCNVD update
  15. 2026-09-07 02:05 UTCEG score recompute
  16. 2026-09-07 02:01 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-20503?
CVE-2026-20503 is a medium vulnerability published on September 7, 2026. In Modem, there is a possible system crash due to a missing bounds check. This could lead to remote denial of service, if a UE has connected to a rogue base station controlled by the attacker, with no additional execution privileges needed. User interaction is not needed for exploitation. Patch ID:…
When was CVE-2026-20503 disclosed?
CVE-2026-20503 was first published in the National Vulnerability Database on September 7, 2026, with the most recent update on September 9, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-20503 actively exploited?
CVE-2026-20503 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 90.8% of all scored CVEs.
What is the CVSS score of CVE-2026-20503?
CVE-2026-20503 has a CVSS v3.1 base score of 5.3 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-20503?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-20503, 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

Explore the affected products and dependency analysis for CVE-2026-20503

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