CVE-2026-13358

MEDIUMPre-NVD 6.56.5—
EchelonGraph scoreMEDIUM confidence

Score 6.5 from GitHub Security Advisory published 2026-08-16. A secondary CVSS source baseline 6.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this week
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.7%CVSS: 6.5Exploit: None knownExposed services: Not assessed

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

The Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin plugin for WordPress is vulnerable to Insecure Direct Object Reference in all versions up to, and including, 1.6.12.10 via the ssa_past_appointments due to missing validation on a user controlled key. This makes it possible for authenticated attackers, with contributor-level access and above, to access appointment records belonging to arbitrary users and harvest the per-appointment ownership tokens (32-character hashes) embedded in the rendered HTML, which can then be used without any authentication to read or modify those appointments including full customer PII such as name, email, phone number, and private notes. The /wp-json/ssa/v1/render-shortcode REST endpoint is registered unconditionally on rest_api_init regardless of whether the Divi theme is installed, and its permission callback only requires current_user_can('edit_posts'), meaning any Contributor-level account is sufficient to trigger this entire exploit chain.

CVSS v3
6.5
EG Score
6.5MEDIUMmedium confidence
EG Risk
30
EG Risk 30/100CISA 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
Severity65% × 45%
Exploitation1% × 40%
Automatability0% × 15%
CISA SSVC: Track at every mission impact level.
Action: No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines, and watch the vendor's advisory for the fix.
EPSS PROB
0.7%
EPSS %ILE
50th
KEV
Not listed

CISA SSVCTrack at every mission impact level.

No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines, and watch the vendor's advisory for the fix.

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

August 16, 2026

Last Modified

August 20, 2026

References (12)

Vendor Advisories for CVE-2026-13358(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 15× in last 7d / 68× 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.

Showing the most recent 100 of 124 total refreshes for this CVE.

  1. 2026-10-05 17:42 UTCEPSS rescore
  2. 2026-10-04 23:21 UTCEPSS rescore
  3. 2026-10-04 21:54 UTCGHSA enrichment
  4. 2026-10-03 19:26 UTCEG score recompute
  5. 2026-10-03 19:26 UTCGHSA enrichment
  6. 2026-10-03 14:25 UTCEPSS rescore
  7. 2026-10-02 16:07 UTCEG score recompute
  8. 2026-10-02 16:07 UTCGHSA enrichment
  9. 2026-10-01 19:49 UTCEPSS rescore
  10. 2026-10-01 14:15 UTCEG score recompute
  11. 2026-10-01 14:15 UTCGHSA enrichment
  12. 2026-09-30 15:02 UTCEPSS rescore
  13. 2026-09-30 12:20 UTCEG score recompute
  14. 2026-09-30 12:20 UTCGHSA enrichment
  15. 2026-09-29 15:20 UTCEPSS rescore
  16. 2026-09-28 13:50 UTCEPSS rescore
  17. 2026-09-28 10:15 UTCEG score recompute
  18. 2026-09-28 10:15 UTCGHSA enrichment
  19. 2026-09-27 08:22 UTCEG score recompute
  20. 2026-09-27 08:22 UTCGHSA enrichment
  21. 2026-09-26 15:58 UTCEPSS rescore
  22. 2026-09-24 16:22 UTCEG score recompute
  23. 2026-09-24 16:22 UTCGHSA enrichment
  24. 2026-09-23 13:47 UTCEPSS rescore
  25. 2026-09-23 12:52 UTCEG score recompute
Show 75 more
  1. 2026-09-23 12:52 UTCGHSA enrichment
  2. 2026-09-22 10:58 UTCEG score recompute
  3. 2026-09-22 10:58 UTCGHSA enrichment
  4. 2026-09-21 09:04 UTCEG score recompute
  5. 2026-09-21 09:04 UTCGHSA enrichment
  6. 2026-09-20 20:15 UTCEPSS rescore
  7. 2026-09-20 05:24 UTCEG score recompute
  8. 2026-09-20 05:24 UTCGHSA enrichment
  9. 2026-09-19 03:31 UTCEG score recompute
  10. 2026-09-19 03:31 UTCGHSA enrichment
  11. 2026-09-18 19:27 UTCEPSS rescore
  12. 2026-09-18 01:38 UTCEG score recompute
  13. 2026-09-18 01:38 UTCGHSA enrichment
  14. 2026-09-16 23:45 UTCEG score recompute
  15. 2026-09-16 23:45 UTCGHSA enrichment
  16. 2026-09-16 05:14 UTCEPSS rescore
  17. 2026-09-15 21:52 UTCEG score recompute
  18. 2026-09-15 21:52 UTCGHSA enrichment
  19. 2026-09-14 19:59 UTCGHSA enrichment
  20. 2026-09-13 17:08 UTCEG score recompute
  21. 2026-09-13 17:08 UTCGHSA enrichment
  22. 2026-09-13 16:46 UTCEPSS rescore
  23. 2026-09-12 15:15 UTCEG score recompute
  24. 2026-09-12 15:15 UTCGHSA enrichment
  25. 2026-09-12 15:00 UTCEPSS rescore
  26. 2026-09-11 14:52 UTCEPSS rescore
  27. 2026-09-11 13:22 UTCEG score recompute
  28. 2026-09-11 13:22 UTCGHSA enrichment
  29. 2026-09-11 09:36 UTCEPSS rescore
  30. 2026-09-10 10:27 UTCEG score recompute
  31. 2026-09-10 10:27 UTCGHSA enrichment
  32. 2026-09-10 09:34 UTCEPSS rescore
  33. 2026-09-09 08:34 UTCEG score recompute
  34. 2026-09-09 08:34 UTCGHSA enrichment
  35. 2026-09-08 22:00 UTCEPSS rescore
  36. 2026-09-08 06:41 UTCEG score recompute
  37. 2026-09-08 06:41 UTCGHSA enrichment
  38. 2026-09-07 16:01 UTCEPSS rescore
  39. 2026-09-07 04:48 UTCEG score recompute
  40. 2026-09-07 04:48 UTCGHSA enrichment
  41. 2026-09-06 13:47 UTCEPSS rescore
  42. 2026-09-05 23:48 UTCEG score recompute
  43. 2026-09-05 23:48 UTCGHSA enrichment
  44. 2026-09-04 21:56 UTCEG score recompute
  45. 2026-09-04 21:56 UTCGHSA enrichment
  46. 2026-09-04 05:06 UTCEPSS rescore
  47. 2026-09-03 19:10 UTCGHSA enrichment
  48. 2026-09-02 17:16 UTCEG score recompute
  49. 2026-09-02 17:16 UTCGHSA enrichment
  50. 2026-09-02 14:11 UTCEPSS rescore
  51. 2026-09-01 13:53 UTCEPSS rescore
  52. 2026-09-01 11:33 UTCEG score recompute
  53. 2026-09-01 11:33 UTCGHSA enrichment
  54. 2026-09-01 04:39 UTCEPSS rescore
  55. 2026-08-31 09:37 UTCEG score recompute
  56. 2026-08-31 09:37 UTCGHSA enrichment
  57. 2026-08-30 19:17 UTCEPSS rescore
  58. 2026-08-30 07:43 UTCEG score recompute
  59. 2026-08-30 07:43 UTCGHSA enrichment
  60. 2026-08-30 01:21 UTCEPSS rescore
  61. 2026-08-29 05:51 UTCEG score recompute
  62. 2026-08-29 05:50 UTCGHSA enrichment
  63. 2026-08-28 21:40 UTCEPSS rescore
  64. 2026-08-28 02:15 UTCEG score recompute
  65. 2026-08-28 02:15 UTCGHSA enrichment
  66. 2026-08-27 14:24 UTCEPSS rescore
  67. 2026-08-27 00:17 UTCEG score recompute
  68. 2026-08-27 00:17 UTCGHSA enrichment
  69. 2026-08-25 22:23 UTCEG score recompute
  70. 2026-08-25 22:23 UTCGHSA enrichment
  71. 2026-08-25 13:48 UTCEPSS rescore
  72. 2026-08-24 20:31 UTCEG score recompute
  73. 2026-08-24 20:31 UTCGHSA enrichment
  74. 2026-08-23 18:38 UTCEG score recompute
  75. 2026-08-23 18:38 UTCGHSA enrichment

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Frequently asked(5)

What is CVE-2026-13358?
CVE-2026-13358 is a medium vulnerability published on August 16, 2026. The Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin plugin for WordPress is vulnerable to Insecure Direct Object Reference in all versions up to, and including, 1.6.12.10 via the ssapastappointments due to missing validation on a user controlled key. This makes it…
When was CVE-2026-13358 disclosed?
CVE-2026-13358 was first published on August 16, 2026, with the most recent update on August 20, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-13358 actively exploited?
CVE-2026-13358 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.7% probability of exploitation in the next 30 days (50th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-13358?
CVE-2026-13358 has a CVSS base score of 6.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-13358?
No fix for CVE-2026-13358 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-2026-13358 are linked in the Vendor Advisories panel on this page.

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