CVE-2026-67204

MEDIUMPre-NVD 5.45.4
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

Score 5.4 from GitHub Security Advisory published 2026-08-24. A secondary CVSS source baseline 5.4; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, a secondary CVSS source
Trending — 3 sources updated this week
5.4EG
EchelonGraph verdictMonitorRemediate within your standard update timelines (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 5.4Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

BookStack before 26.05.4 contains a broken access control vulnerability that allows authenticated API users with image-update or image-delete permissions to manipulate other users' avatars by exploiting missing content-type restrictions in the Image Gallery API endpoints. Attackers can supply a user avatar's ID to the API controller, which loads any image type without the web controller's gallery and drawio restrictions, and when the avatar's uploaded_to field matches a page ID accessible to the attacker, the authorization check passes allowing the attacker to rename, replace, or delete the target user's avatar without requiring user-management permission.

CVSS v3
5.4
EG Score
5.4MEDIUMmedium confidence
EG Risk
24
EG Risk 24/100

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 (value × EchelonGraph’s weight)
Severity54% × 45%
The EG Score, 5.4 of 10.
Exploitation0.4% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.4%
EPSS %ILE
33rd
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

August 24, 2026

Last Modified

October 12, 2026

Advisory Details (4)

Auto-updated Aug 24, 2026
Patch available. Sources: github_release.
Web page

BookStack < 26.05.4 Broken Access Control via Image Gallery API | Advisories | VulnCheck

https://www.vulncheck.com/advisories/bookstack-broken-access-control-via-image-gallery-api
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
Web page

Cookie monster!

https://codeberg.org/bookstack/bookstack/releases/tag/v26.05.4
Web page

BookStack Security Release v26.05.4 · BookStack

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

Vendor Advisories for CVE-2026-67204(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 18× in last 7d / 76× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 99 of 134 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 1 repeat row among the latest 100 is merged into the row it repeats. The 35 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  2. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  3. 2026-10-12 15:29 UTCEG score recompute
  4. 2026-10-12 15:29 UTCGHSA enrichmentGHSA-v32j-vgqh-f22g · GitHub CVSS 5.4
  5. 2026-10-11 19:31 UTCEG score recompute
  6. 2026-10-11 16:46 UTCEG score recompute
  7. 2026-10-11 14:07 UTCEG score recompute
  8. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  9. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  10. 2026-10-10 12:39 UTCEG score recompute
  11. 2026-10-10 12:38 UTCGHSA enrichmentGHSA-v32j-vgqh-f22g · GitHub CVSS 5.4
  12. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  13. 2026-10-09 05:32 UTCEG score recompute
  14. 2026-10-09 05:32 UTCGHSA enrichmentGHSA-v32j-vgqh-f22g · GitHub CVSS 5.4
  15. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  16. 2026-10-08 04:40 UTCEG score recompute
  17. 2026-10-08 04:40 UTCGHSA enrichmentGHSA-v32j-vgqh-f22g · GitHub CVSS 5.4
  18. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  19. 2026-10-07 03:48 UTCEG score recompute
  20. 2026-10-07 03:48 UTCGHSA enrichmentGHSA-v32j-vgqh-f22g · GitHub CVSS 5.4
  21. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  22. 2026-10-06 02:51 UTCEG score recompute
  23. 2026-10-06 02:51 UTCGHSA enrichmentGHSA-v32j-vgqh-f22g · GitHub CVSS 5.4
  24. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  25. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
Show 74 more
  1. 2026-10-04 20:42 UTCGHSA enrichmentGHSA-v32j-vgqh-f22g · GitHub CVSS 5.4
  2. 2026-10-03 17:15 UTCEG score recompute
  3. 2026-10-03 17:15 UTCGHSA enrichmentGHSA-v32j-vgqh-f22g · GitHub CVSS 5.4
  4. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  5. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  6. 2026-10-02 16:19 UTCEG score recompute
  7. 2026-10-02 16:19 UTCGHSA enrichmentGHSA-v32j-vgqh-f22g · GitHub CVSS 5.4
  8. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  9. 2026-10-01 15:28 UTCEG score recompute
  10. 2026-10-01 15:28 UTCGHSA enrichmentGHSA-v32j-vgqh-f22g · GitHub CVSS 5.4
  11. 2026-10-01 08:05 UTCEG score recompute
  12. 2026-10-01 08:05 UTCGHSA enrichmentGHSA-v32j-vgqh-f22g · GitHub CVSS 5.4
  13. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  14. 2026-09-30 07:13 UTCEG score recompute
  15. 2026-09-30 07:13 UTCGHSA enrichmentGHSA-v32j-vgqh-f22g · GitHub CVSS 5.4
  16. 2026-09-29 02:22 UTCEG score recompute
  17. 2026-09-29 02:22 UTCGHSA enrichmentGHSA-v32j-vgqh-f22g · GitHub CVSS 5.4
  18. 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  19. 2026-09-28 01:30 UTCEG score recompute
  20. 2026-09-28 01:30 UTCGHSA enrichmentGHSA-v32j-vgqh-f22g · GitHub CVSS 5.4
  21. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  22. 2026-09-27 00:38 UTCEG score recompute
  23. 2026-09-27 00:38 UTCGHSA enrichmentGHSA-v32j-vgqh-f22g · GitHub CVSS 5.4
  24. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  25. 2026-09-24 21:20 UTCEG score recompute
  26. 2026-09-24 21:20 UTCGHSA enrichmentGHSA-v32j-vgqh-f22g · GitHub CVSS 5.4
  27. 2026-09-24 14:40 UTCEG score recompute
  28. 2026-09-24 14:40 UTCGHSA enrichmentGHSA-v32j-vgqh-f22g · GitHub CVSS 5.4
  29. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  30. 2026-09-23 13:44 UTCEG score recompute
  31. 2026-09-23 13:44 UTCGHSA enrichmentGHSA-v32j-vgqh-f22g · GitHub CVSS 5.4
  32. 2026-09-22 12:52 UTCEG score recompute
  33. 2026-09-22 12:52 UTCGHSA enrichmentGHSA-v32j-vgqh-f22g · GitHub CVSS 5.4
  34. 2026-09-21 11:59 UTCEG score recompute
  35. 2026-09-21 11:59 UTCGHSA enrichmentGHSA-v32j-vgqh-f22g · GitHub CVSS 5.4
  36. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  37. 2026-09-20 11:07 UTCEG score recompute
  38. 2026-09-20 11:07 UTCGHSA enrichmentGHSA-v32j-vgqh-f22g · GitHub CVSS 5.4
  39. 2026-09-19 10:16 UTCEG score recompute
  40. 2026-09-19 10:15 UTCGHSA enrichmentGHSA-v32j-vgqh-f22g · GitHub CVSS 5.4
  41. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  42. 2026-09-18 09:23 UTCEG score recompute
  43. 2026-09-18 09:23 UTCGHSA enrichmentGHSA-v32j-vgqh-f22g · GitHub CVSS 5.4
  44. 2026-09-17 08:31 UTCEG score recompute
  45. 2026-09-17 08:31 UTCGHSA enrichmentGHSA-v32j-vgqh-f22g · GitHub CVSS 5.4
  46. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  47. 2026-09-16 07:37 UTCEG score recompute
  48. 2026-09-16 07:37 UTCGHSA enrichmentGHSA-v32j-vgqh-f22g · GitHub CVSS 5.4
  49. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  50. 2026-09-15 06:43 UTCEG score recompute
  51. 2026-09-15 06:43 UTCGHSA enrichmentGHSA-v32j-vgqh-f22g · GitHub CVSS 5.4
  52. 2026-09-14 05:51 UTCEG score recompute
  53. 2026-09-14 05:51 UTCGHSA enrichmentGHSA-v32j-vgqh-f22g · GitHub CVSS 5.4
  54. 2026-09-13 05:00 UTCEG score recompute
  55. 2026-09-13 05:00 UTCGHSA enrichmentGHSA-v32j-vgqh-f22g · GitHub CVSS 5.4
  56. 2026-09-12 04:08 UTCEG score recompute
  57. 2026-09-12 04:08 UTCGHSA enrichmentGHSA-v32j-vgqh-f22g · GitHub CVSS 5.4
  58. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  59. 2026-09-11 09:37 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  60. 2026-09-11 03:15 UTCEG score recompute
  61. 2026-09-11 03:15 UTCGHSA enrichmentGHSA-v32j-vgqh-f22g · GitHub CVSS 5.4
  62. 2026-09-10 02:23 UTCGHSA enrichmentGHSA-v32j-vgqh-f22g · GitHub CVSS 5.4
  63. 2026-09-09 01:31 UTCEG score recompute
  64. 2026-09-09 01:31 UTCGHSA enrichmentGHSA-v32j-vgqh-f22g · GitHub CVSS 5.4
  65. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  66. 2026-09-07 20:34 UTCEG score recompute
  67. 2026-09-07 20:33 UTCGHSA enrichmentGHSA-v32j-vgqh-f22g · GitHub CVSS 5.4
  68. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  69. 2026-09-06 19:41 UTCEG score recompute
  70. 2026-09-06 19:41 UTCGHSA enrichmentGHSA-v32j-vgqh-f22g · GitHub CVSS 5.4
  71. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  72. 2026-09-05 18:43 UTCEG score recompute
  73. 2026-09-05 18:43 UTCGHSA enrichmentGHSA-v32j-vgqh-f22g · GitHub CVSS 5.4
  74. 2026-09-05 15:31 UTCEPSS rescoreEPSS 0.2% · 14th percentile

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-67204?
CVE-2026-67204 is a medium-severity vulnerability; its CVE record was published on August 24, 2026. BookStack before 26.05.4 contains a broken access control vulnerability that allows authenticated API users with image-update or image-delete permissions to manipulate other users' avatars by exploiting missing content-type restrictions in the Image Gallery API endpoints. Attackers can supply a…
When was CVE-2026-67204 made public?
CVE-2026-67204 was made public on August 24, 2026: that is the date its CVE record's CNA, VulnCheck, gives for when the vulnerability was made public. The CVE record itself was published on August 24, 2026. EchelonGraph's copy of the record carries a last-modified date of October 12, 2026; the record at its source may have been updated since.
Is CVE-2026-67204 actively exploited?
CVE-2026-67204 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (33rd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-67204?
CVE-2026-67204 has a CVSS base score of 5.4 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-67204?
A fix for CVE-2026-67204 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-67204 are linked in the Vendor Advisories panel on this page.

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