CVE-2026-84695

HIGHPre-NVD 8.78.7—
EchelonGraph scoreHIGH confidence

Score 8.7 from GitHub Security Advisory (severity: CRITICAL) published 2026-09-02. a secondary CVSS source baseline 8.7; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this week
8.7EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.7Exploit: None knownExposed: 0

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

BookStack before 26.05.4 contains a stored cross-site scripting vulnerability in the drawing upload endpoint that accepts unvalidated base64 content and stores it without content inspection. Attackers with editor permissions can upload SVG files containing scripts that execute in administrator browsers when accessed through the image gallery API without content-type validation or CSP headers.

CVSS v3
8.7
EG Score
8.7(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
Severity87% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
38%
KEV
Not listed

Published

September 2, 2026

Last Modified

September 8, 2026

Advisory Details (6)

Auto-updated Sep 2, 2026
Patch available. Sources: github_commit, github_release.
generic

BookStack before 26.05.4 Stored XSS via Drawing Upload | Advisories | VulnCheck

https://www.vulncheck.com/advisories/bookstack-before-26.05.4-stored-xss-via-drawing-upload
generic

BookStack Security Release v26.05.4 · BookStack

https://www.bookstackapp.com/blog/bookstack-release-v26-05-4/
github_release Patch Available

BookStack v26.05.4

Patch available: BookStackApp/BookStack v26.05.4

https://github.com/BookStackApp/BookStack/releases/tag/v26.05.4
github_commit Patch Available

commit ac0348a79f3d (BookStackApp/BookStack)

Patch available: BookStackApp/BookStack v26.05.4 (contains commit ac0348a79f3d)

https://github.com/BookStackApp/BookStack/commit/ac0348a79f3ddd004ca87703948cb9c7d19a420a
generic

BookStack/app/Uploads/ImageService.php at v26.05.3 · BookStackApp/BookStack · GitHub

https://github.com/BookStackApp/BookStack/blob/v26.05.3/app/Uploads/ImageService.php
generic

GitHub - BookStackApp/BookStack: NOW MANAGED ON CODEBERG · GitHub

https://github.com/BookStackApp/BookStack

Vendor Advisories for CVE-2026-84695(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 27× in last 7d / 92× 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. 2026-09-25 07:29 UTCGHSA enrichment
  2. 2026-09-24 19:39 UTCEG score recompute
  3. 2026-09-24 19:39 UTCGHSA enrichment
  4. 2026-09-24 14:04 UTCEPSS rescore
  5. 2026-09-24 07:46 UTCGHSA enrichment
  6. 2026-09-23 19:57 UTCEG score recompute
  7. 2026-09-23 19:57 UTCGHSA enrichment
  8. 2026-09-23 17:54 UTCEPSS rescore
  9. 2026-09-23 08:09 UTCGHSA enrichment
  10. 2026-09-22 20:20 UTCEG score recompute
  11. 2026-09-22 20:20 UTCGHSA enrichment
  12. 2026-09-22 16:01 UTCEPSS rescore
  13. 2026-09-22 08:31 UTCEG score recompute
  14. 2026-09-22 08:31 UTCGHSA enrichment
  15. 2026-09-21 21:09 UTCEPSS rescore
  16. 2026-09-21 20:41 UTCGHSA enrichment
  17. 2026-09-21 08:52 UTCGHSA enrichment
  18. 2026-09-20 20:43 UTCEG score recompute
  19. 2026-09-20 20:43 UTCGHSA enrichment
  20. 2026-09-20 20:16 UTCEPSS rescore
  21. 2026-09-20 08:53 UTCGHSA enrichment
  22. 2026-09-19 21:04 UTCEG score recompute
  23. 2026-09-19 21:04 UTCGHSA enrichment
  24. 2026-09-19 09:14 UTCGHSA enrichment
  25. 2026-09-18 21:24 UTCEG score recompute
Show 67 more
  1. 2026-09-18 21:24 UTCGHSA enrichment
  2. 2026-09-18 19:28 UTCEPSS rescore
  3. 2026-09-18 09:01 UTCGHSA enrichment
  4. 2026-09-17 21:12 UTCEG score recompute
  5. 2026-09-17 21:12 UTCGHSA enrichment
  6. 2026-09-17 19:32 UTCEPSS rescore
  7. 2026-09-17 09:23 UTCGHSA enrichment
  8. 2026-09-16 21:34 UTCEG score recompute
  9. 2026-09-16 21:34 UTCGHSA enrichment
  10. 2026-09-16 14:09 UTCEPSS rescore
  11. 2026-09-16 09:45 UTCEG score recompute
  12. 2026-09-16 09:45 UTCGHSA enrichment
  13. 2026-09-16 05:15 UTCEPSS rescore
  14. 2026-09-15 21:55 UTCGHSA enrichment
  15. 2026-09-15 10:06 UTCEG score recompute
  16. 2026-09-15 10:06 UTCGHSA enrichment
  17. 2026-09-15 03:12 UTCEPSS rescore
  18. 2026-09-15 03:12 UTCEPSS rescore
  19. 2026-09-14 22:15 UTCGHSA enrichment
  20. 2026-09-14 10:24 UTCGHSA enrichment
  21. 2026-09-13 22:35 UTCEG score recompute
  22. 2026-09-13 22:35 UTCGHSA enrichment
  23. 2026-09-13 10:46 UTCGHSA enrichment
  24. 2026-09-12 22:57 UTCEG score recompute
  25. 2026-09-12 22:57 UTCGHSA enrichment
  26. 2026-09-12 11:07 UTCGHSA enrichment
  27. 2026-09-11 23:17 UTCEG score recompute
  28. 2026-09-11 23:17 UTCGHSA enrichment
  29. 2026-09-11 14:53 UTCEPSS rescore
  30. 2026-09-11 14:53 UTCEPSS rescore
  31. 2026-09-11 11:07 UTCEG score recompute
  32. 2026-09-11 11:06 UTCGHSA enrichment
  33. 2026-09-10 23:17 UTCGHSA enrichment
  34. 2026-09-10 11:28 UTCEG score recompute
  35. 2026-09-10 11:28 UTCGHSA enrichment
  36. 2026-09-09 23:34 UTCGHSA enrichment
  37. 2026-09-09 08:39 UTCEG score recompute
  38. 2026-09-09 08:39 UTCGHSA enrichment
  39. 2026-09-08 22:01 UTCEPSS rescore
  40. 2026-09-08 20:50 UTCGHSA enrichment
  41. 2026-09-08 02:41 UTCEG score recompute
  42. 2026-09-08 02:41 UTCGHSA enrichment
  43. 2026-09-07 14:53 UTCGHSA enrichment
  44. 2026-09-07 02:53 UTCGHSA enrichment
  45. 2026-09-06 15:02 UTCEG score recompute
  46. 2026-09-06 15:02 UTCGHSA enrichment
  47. 2026-09-06 13:48 UTCEPSS rescore
  48. 2026-09-06 03:12 UTCEG score recompute
  49. 2026-09-06 03:12 UTCGHSA enrichment
  50. 2026-09-05 15:31 UTCEPSS rescore
  51. 2026-09-05 15:21 UTCGHSA enrichment
  52. 2026-09-05 03:32 UTCGHSA enrichment
  53. 2026-09-04 15:43 UTCEG score recompute
  54. 2026-09-04 15:43 UTCGHSA enrichment
  55. 2026-09-04 05:07 UTCEPSS rescore
  56. 2026-09-04 03:53 UTCGHSA enrichment
  57. 2026-09-03 16:02 UTCGHSA enrichment
  58. 2026-09-03 04:13 UTCEG score recompute
  59. 2026-09-03 04:13 UTCGHSA enrichment
  60. 2026-09-02 16:20 UTCEG score recompute
  61. 2026-09-02 16:20 UTCGHSA enrichment
  62. 2026-09-02 14:12 UTCEPSS rescore
  63. 2026-09-02 13:16 UTCEG score recompute
  64. 2026-09-02 13:16 UTCGHSA enrichment
  65. 2026-09-02 01:25 UTCEG score recompute
  66. 2026-09-02 01:12 UTCEG score recompute
  67. 2026-09-02 01:10 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-84695?
CVE-2026-84695 is a high vulnerability published on September 2, 2026. BookStack before 26.05.4 contains a stored cross-site scripting vulnerability in the drawing upload endpoint that accepts unvalidated base64 content and stores it without content inspection. Attackers with editor permissions can upload SVG files containing scripts that execute in administrator…
When was CVE-2026-84695 disclosed?
CVE-2026-84695 was first published in the National Vulnerability Database on September 2, 2026, with the most recent update on September 8, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-84695 actively exploited?
CVE-2026-84695 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 62.0% of all scored CVEs.
What is the CVSS score of CVE-2026-84695?
CVE-2026-84695 has a CVSS v3 base score of 8.7 (NVD).
How do I remediate CVE-2026-84695?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-84695, 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-2026-84695

Explore →

Is Your Infrastructure Affected by CVE-2026-84695?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Book a Demo →Browse All CVEs