CVE-2026-63097

MEDIUMPre-NVD 4.34.3—
EchelonGraph scoreMEDIUM confidence

Score 4.3 from GitHub Security Advisory published 2026-07-17. the CNA's CVSS baseline 4.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cna:vulncheck, epss, ghsa
Trending — 3 sources updated this weekElevated
4.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 4.3Exploit: Elevated riskExposed: 0

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

Dendrite through 0.13.8 contains an improper access control vulnerability in the syncapi /context endpoint (syncapi/routing/context.go) that allows authenticated local users to access post-leave room state events by exploiting a flawed membership check that evaluates only the RoomExists field while ignoring IsInRoom, HasBeenInRoom, and Membership fields. Attackers who have left a room can call the rooms context API endpoint for a previously permitted event and receive unfiltered current room state that the /messages and /sync endpoints correctly withhold.

CVSS v3
4.3
EG Score
4.3(medium)
EG Risk
35(Track)
EG Risk 35/100SSVC: 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
Severity43% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
19%
KEV
Not listed

Published

July 17, 2026

Last Modified

July 28, 2026

Advisory Details (2)

Auto-updated Jul 17, 2026
No patch confirmed yet.
generic

Dendrite 0.13.8 syncapi /context Endpoint Post-Leave State Exposure | Advisories | VulnCheck

https://www.vulncheck.com/advisories/dendrite-syncapi-context-endpoint-post-leave-state-exposure
generic

oss/dendrite.md at main · geo-chen/oss · GitHub

https://github.com/geo-chen/oss/blob/main/dendrite.md#finding-3-context-returns-current-room-state-to-non-members-and-left-users-history-visibility-bypass

Vendor Advisories for CVE-2026-63097(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 8× in last 7d / 58× 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 143 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-63097?
CVE-2026-63097 is a medium vulnerability published on July 17, 2026. Dendrite through 0.13.8 contains an improper access control vulnerability in the syncapi /context endpoint (syncapi/routing/context.go) that allows authenticated local users to access post-leave room state events by exploiting a flawed membership check that evaluates only the RoomExists field while…
When was CVE-2026-63097 disclosed?
CVE-2026-63097 was first published in the National Vulnerability Database on July 17, 2026, with the most recent update on July 28, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-63097 actively exploited?
CVE-2026-63097 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 81.2% of all scored CVEs.
What is the CVSS score of CVE-2026-63097?
CVE-2026-63097 has a CVSS v4.0 base score of 4.3 (CNA self-assessment; NVD's own analysis pending).
How do I remediate CVE-2026-63097?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-63097, 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.

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