CVE-2023-39953

MEDIUMNVD 4.84.8—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 4.8 under NVD CVSS v3. EPSS exploit probability: 0.6%, top 30% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
4.8
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 4.8Exploit: NoneExposed: 0

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

user_oidc provides the OIDC connect user backend for Nextcloud, an open-source cloud platform. Starting in version 1.0.0 and prior to version 1.3.3, missing verification of the issuer would have allowed an attacker to perform a man-in-the-middle attack returning corrupted or known token they also have access to. user_oidc 1.3.3 contains a patch. No known workarounds are available.

CVSS v3
4.8
EG Score
4.8(medium)
EPSS
35.9%
KEV
Not listed

Published

August 10, 2023

Last Modified

November 21, 2024

References (6)

Weakness Classification(1)

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

Data Freshness Timeline

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

Frequently asked(5)

What is CVE-2023-39953?
CVE-2023-39953 is a medium vulnerability published on August 10, 2023. useroidc provides the OIDC connect user backend for Nextcloud, an open-source cloud platform. Starting in version 1.0.0 and prior to version 1.3.3, missing verification of the issuer would have allowed an attacker to perform a man-in-the-middle attack returning corrupted or known token they also…
When was CVE-2023-39953 disclosed?
CVE-2023-39953 was first published in the National Vulnerability Database on August 10, 2023, 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-2023-39953 actively exploited?
CVE-2023-39953 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 35.9% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2023-39953?
CVE-2023-39953 has a CVSS v3 base score of 4.8 (NVD).
How do I remediate CVE-2023-39953?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2023-39953, 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-2023-39953

Explore →

Is Your Infrastructure Affected by CVE-2023-39953?

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

Start Free Scan →Browse All CVEs