CVE-2026-16536

MEDIUMPre-NVD 5.35.3—
EchelonGraph scoreHIGH confidence

Score 5.3 from GitHub Security Advisory published 2026-08-04. 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.

The Simple Google Calendar Outlook Events Widget WordPress plugin before 3.1.0 does not validate a user-supplied URL before performing a server-side request, allowing unauthenticated attackers to perform Server-Side Request Forgery attacks and, in some cases, read the response of the internal request.

CVSS v3
5.3
EG Score
5.3(high)
EG Risk
39(Track)
EG Risk 39/100SSVC: 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%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
9%
KEV
Not listed

Published

August 4, 2026

Last Modified

August 4, 2026

Advisory Details (1)

Auto-updated Aug 4, 2026
🔬 Proof of concept available. No patch confirmed yet.
generic🟡 PoC Available

Simple Google Calendar Outlook Events Widget < 3.1.0 – Unauthenticated SSRF via calendar_id | CVE 2026-16536 | Plugin Vulnerabilities

https://wpscan.com/vulnerability/effa5549-ecfa-45ba-9044-7345d674c2ca/

Vendor Advisories for CVE-2026-16536(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 20× in last 7d / 56× 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. 2026-08-20 22:55 UTCEPSS rescore
  2. 2026-08-20 22:37 UTCGHSA enrichment
  3. 2026-08-20 00:57 UTCEG score recompute
  4. 2026-08-20 00:57 UTCGHSA enrichment
  5. 2026-08-19 17:03 UTCEPSS rescore
  6. 2026-08-19 03:17 UTCEG score recompute
  7. 2026-08-19 03:17 UTCGHSA enrichment
  8. 2026-08-18 13:48 UTCEPSS rescore
  9. 2026-08-18 05:30 UTCGHSA enrichment
  10. 2026-08-17 07:46 UTCEG score recompute
  11. 2026-08-17 07:46 UTCGHSA enrichment
  12. 2026-08-16 14:56 UTCEPSS rescore
  13. 2026-08-16 10:06 UTCEG score recompute
  14. 2026-08-16 10:06 UTCGHSA enrichment
  15. 2026-08-16 02:14 UTCEPSS rescore
  16. 2026-08-15 12:27 UTCEG score recompute
  17. 2026-08-15 12:27 UTCGHSA enrichment
  18. 2026-08-15 01:30 UTCEPSS rescore
  19. 2026-08-14 14:46 UTCEG score recompute
  20. 2026-08-14 14:46 UTCGHSA enrichment
  21. 2026-08-13 22:00 UTCEPSS rescore
  22. 2026-08-13 17:06 UTCGHSA enrichment
  23. 2026-08-12 19:27 UTCEG score recompute
  24. 2026-08-12 19:27 UTCGHSA enrichment
  25. 2026-08-12 13:50 UTCEPSS rescore
Show 31 more
  1. 2026-08-11 21:47 UTCEG score recompute
  2. 2026-08-11 21:47 UTCGHSA enrichment
  3. 2026-08-11 13:42 UTCEPSS rescore
  4. 2026-08-11 00:07 UTCEG score recompute
  5. 2026-08-11 00:07 UTCGHSA enrichment
  6. 2026-08-11 00:00 UTCEPSS rescore
  7. 2026-08-10 02:27 UTCEG score recompute
  8. 2026-08-10 02:27 UTCGHSA enrichment
  9. 2026-08-09 13:46 UTCEPSS rescore
  10. 2026-08-09 04:48 UTCEG score recompute
  11. 2026-08-09 04:48 UTCGHSA enrichment
  12. 2026-08-08 16:37 UTCEPSS rescore
  13. 2026-08-08 07:08 UTCEG score recompute
  14. 2026-08-08 07:08 UTCGHSA enrichment
  15. 2026-08-07 09:28 UTCEG score recompute
  16. 2026-08-07 09:28 UTCGHSA enrichment
  17. 2026-08-06 13:46 UTCEPSS rescore
  18. 2026-08-06 11:48 UTCEG score recompute
  19. 2026-08-06 11:48 UTCGHSA enrichment
  20. 2026-08-05 19:17 UTCEPSS rescore
  21. 2026-08-05 14:08 UTCEG score recompute
  22. 2026-08-05 14:08 UTCGHSA enrichment
  23. 2026-08-04 15:20 UTCEG score recompute
  24. 2026-08-04 15:20 UTCGHSA enrichment
  25. 2026-08-04 15:10 UTCEPSS rescore
  26. 2026-08-04 14:48 UTCEG score recompute▲ 5.30
  27. 2026-08-04 14:48 UTCGHSA enrichment
  28. 2026-08-04 14:47 UTCMITRE cvelistV5CVSS v3 → 5.3 · severity → MEDIUM
  29. 2026-08-04 07:17 UTCNVD update
  30. 2026-08-04 06:35 UTCEG score recompute
  31. 2026-08-04 06:33 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-16536?
CVE-2026-16536 is a medium vulnerability published on August 4, 2026. The Simple Google Calendar Outlook Events Widget WordPress plugin before 3.1.0 does not validate a user-supplied URL before performing a server-side request, allowing unauthenticated attackers to perform Server-Side Request Forgery attacks and, in some cases, read the response of the internal…
When was CVE-2026-16536 disclosed?
CVE-2026-16536 was first published in the National Vulnerability Database on August 4, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-16536 actively exploited?
CVE-2026-16536 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 90.7% of all scored CVEs.
What is the CVSS score of CVE-2026-16536?
CVE-2026-16536 has a CVSS v3.1 base score of 5.3 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-16536?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-16536, 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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