CVE-2021-26918

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2022-05-24. NVD baseline CVSS 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Elevated
9.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 3%CVSS: 9.8Exploit: NoneExposed: 0

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

The ProBot bot through 2021-02-08 for Discord might allow attackers to interfere with the intended purpose of the "Send an image when a user joins the server" feature (or possibly have unspecified other impact) because the uploader web service allows double extensions (such as .html.jpg) with the text/html content type. NOTE: there may not be cases in which an uploader web service is customer controlled; however, the nature of the issue has substantial interaction with customer controlled configuration. NOTE: the vendor states "This is just an uploader (like any other one) which uploads files to cloud storage and accepts various file types. There is no kind of vulnerability and it won't compromise either the client side or the server side.

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
75(Attend)
EG Risk 75/100SSVC: Attend

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
Severity98% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS
83.6%
KEV
Not listed

Published

February 9, 2021

Last Modified

November 21, 2024

Advisory Details (2)

Auto-updated May 26, 2026
No patch confirmed yet.
generic

bypasss

https://raw.githubusercontent.com/TheLastVvV/Vulnerability-Reports-and-CVE/main/Reports/Discord%20Probot%20-%20Unrestricted%20File%20Upload.txt
generic

Packet Storm

http://packetstormsecurity.com/files/161347/Discord-Probot-Arbitrary-File-Upload.html

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

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

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2021-26918?
CVE-2021-26918 is a critical vulnerability published on February 9, 2021. The ProBot bot through 2021-02-08 for Discord might allow attackers to interfere with the intended purpose of the "Send an image when a user joins the server" feature (or possibly have unspecified other impact) because the uploader web service allows double extensions (such as .html.jpg) with the…
When was CVE-2021-26918 disclosed?
CVE-2021-26918 was first published in the National Vulnerability Database on February 9, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-26918 actively exploited?
CVE-2021-26918 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 83.6% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-26918?
CVE-2021-26918 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2021-26918?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-26918, 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-2021-26918

Explore →

Is Your Infrastructure Affected by CVE-2021-26918?

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

Start Free Scan →Browse All CVEs