CVE-2023-39953

MEDIUMNVD 4.84.8—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 4.8 under NVD CVSS v3. EPSS exploit probability: 0.5% (43rd percentile of EPSS-scored CVEs). 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
4.8EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.5%CVSS: 4.8Exploit: None knownExposed services: Not assessed

A fix is referenced (a reference tagged "Patch", often a source commit), but no release containing it is confirmed — find the release that contains it; until it is applied, mitigate (WAF / firewall / segmentation).

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
4.8MEDIUMmedium confidence
EG Risk
22
EG Risk 22/100CISA SSVC

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
Severity48% × 45%
Exploitation1% × 40%
Automatability0% × 15%
CISA SSVC: Track at every mission impact level.
Action: A fix is referenced, but no release containing it is confirmed. Check the referenced fix and the vendor's advisory for a release that contains it and apply that within your standard update timelines; until then, restrict network exposure of the affected system or apply the vendor's mitigation.
EPSS PROB
0.5%
EPSS %ILE
43rd
KEV
Not listed

CISA SSVCTrack at every mission impact level.

A fix is referenced, but no release containing it is confirmed. Check the referenced fix and the vendor's advisory for a release that contains it and apply that within your standard update timelines; until then, restrict network exposure of the affected system or apply the vendor's mitigation.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

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 8× in last 7d / 33× 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 199 total refreshes for this CVE.

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

Related CVEs(same CWE)

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 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 0.5% probability of exploitation in the next 30 days (43rd percentile of EPSS-scored CVEs).
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?
A fix for CVE-2023-39953 is referenced (a reference tagged "Patch", often a source commit), but EchelonGraph has no release containing it on record. Check that reference and the vendor's advisory for a release that contains the fix and update to it; until then, restrict network exposure of the affected system or apply the vendor's mitigation.

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.

Book a Demo →Browse All CVEs