CVE-2026-49140

MEDIUMPre-NVD 4.34.3—
EchelonGraph scoreMEDIUM confidence

Score 4.3 from GitHub Security Advisory published 2026-06-01. a secondary CVSS source baseline 4.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Elevated
4.3
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 4.3Exploit: NoneExposed: 0

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

Nanobot prior to version 0.2.1 contains a denial of service vulnerability in the Matrix channel media download handler that allows authenticated room members to exhaust process memory and bandwidth by sending media events with missing or invalid size metadata. Attackers can send multiple concurrent Matrix media events with omitted or invalid declared sizes to trigger simultaneous large media downloads that fully materialize response bodies before post-download rejection, consuming process resources until service degradation occurs.

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
18.7%
KEV
Not listed

Published

June 1, 2026

Last Modified

July 22, 2026

Advisory Details (4)

Auto-updated Jun 17, 2026
Patch available. Sources: github_pr, github_release, github_commit.
github_pr Patch Available

[security] fix(matrix): bound inbound media downloads

Patch available: HKUDS/nanobot v0.2.1 (PR #4106 merged 2026-05-30)

https://github.com/HKUDS/nanobot/pull/4106
generic

Nanobot < 0.2.1 Denial of Service via Matrix Media Download Handler | Advisories | VulnCheck

https://www.vulncheck.com/advisories/nanobot-denial-of-service-via-matrix-media-download-handler
github_release Patch Available

v0.2.1

Patch available: HKUDS/nanobot v0.2.1

https://github.com/HKUDS/nanobot/releases/tag/v0.2.1
github_commit Patch Available

commit 1d4000560dff (HKUDS/nanobot)

Patch available: HKUDS/nanobot v0.2.1 (contains commit 1d4000560dff)

https://github.com/HKUDS/nanobot/commit/1d4000560dfff1acb83f5c5ca8ef3ab1f092bd14

Vendor Advisories for CVE-2026-49140(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 9× in last 7d / 44× 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 102 total refreshes for this CVE.

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

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Frequently asked(5)

What is CVE-2026-49140?
CVE-2026-49140 is a medium vulnerability published on June 1, 2026. Nanobot prior to version 0.2.1 contains a denial of service vulnerability in the Matrix channel media download handler that allows authenticated room members to exhaust process memory and bandwidth by sending media events with missing or invalid size metadata. Attackers can send multiple concurrent…
When was CVE-2026-49140 disclosed?
CVE-2026-49140 was first published in the National Vulnerability Database on June 1, 2026, with the most recent update on July 22, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-49140 actively exploited?
CVE-2026-49140 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 18.7% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-49140?
CVE-2026-49140 has a CVSS v3 base score of 4.3 (NVD).
How do I remediate CVE-2026-49140?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-49140, 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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