CVE-2023-27536

MEDIUMNVD 5.99.8▲
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2023-03-30. NVD baseline CVSS 5.9; sources differ by 3.9.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Elevated
5.9
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 2%CVSS: 5.9Exploit: NoneExposed: 0

A fix is available — apply it.

An authentication bypass vulnerability exists libcurl <8.0.0 in the connection reuse feature which can reuse previously established connections with incorrect user permissions due to a failure to check for changes in the CURLOPT_GSSAPI_DELEGATION option. This vulnerability affects krb5/kerberos/negotiate/GSSAPI transfers and could potentially result in unauthorized access to sensitive information. The safest option is to not reuse connections if the CURLOPT_GSSAPI_DELEGATION option has been changed.

CVSS v3
5.9
EG Score
9.8(medium)
EPSS
72.7%
KEV
Not listed

Published

March 30, 2023

Last Modified

February 14, 2025

References (10)

Patch Availability(5)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntucurl (7.81.0-1ubuntu1.10) @ jammy2026-05-25ubuntu
ubuntucurl (7.35.0-1ubuntu2.20+esm15) @ trusty2026-05-25ubuntu
redhatcurl-0:7.61.1-22.el8_6.122024-01-25redhat
redhatcurl-0:7.76.1-26.el92023-11-07redhat
redhatcurl-0:7.61.1-30.el8_8.32023-08-08redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(2)

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

All Vendor Advisories

(6)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

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

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Frequently asked(5)

What is CVE-2023-27536?
CVE-2023-27536 is a medium vulnerability published on March 30, 2023. An authentication bypass vulnerability exists libcurl <8.0.0 in the connection reuse feature which can reuse previously established connections with incorrect user permissions due to a failure to check for changes in the CURLOPTGSSAPIDELEGATION option. This vulnerability affects…
When was CVE-2023-27536 disclosed?
CVE-2023-27536 was first published in the National Vulnerability Database on March 30, 2023, with the most recent update on February 14, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2023-27536 actively exploited?
CVE-2023-27536 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 72.7% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2023-27536?
CVE-2023-27536 has a CVSS v3 base score of 5.9 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.8.
How do I remediate CVE-2023-27536?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2023-27536, 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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