CVE-2026-4873

MEDIUMNVD 5.95.9—
EchelonGraph scoreMEDIUM confidence

Score 5.9 from GitHub Security Advisory published 2026-05-13. NVD baseline CVSS 5.9; sources differ by 0.0.

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

A fix is available — apply it.

A vulnerability exists where a connection requiring TLS incorrectly reuses an existing unencrypted connection from the same connection pool. If an initial transfer is made in clear-text (via IMAP, SMTP, or POP3), a subsequent request to that same host bypasses the TLS requirement and instead transmit data unencrypted.

CVSS v3
5.9
EG Score
5.9(medium)
EPSS
24.9%
KEV
Not listed

Published

May 13, 2026

Last Modified

May 14, 2026

Advisory Details (4)

Auto-updated May 14, 2026
⚠️ Active exploitation confirmed. No patch confirmed yet.
generic🔴 Active Exploitation

oss-security - [ADVISORY] curl: CVE-2026-4873: connection reuse ignores TLS requirement

http://www.openwall.com/lists/oss-security/2026/04/29/7
generic

HackerOne

https://hackerone.com/reports/3621851
generic
https://curl.se/docs/CVE-2026-4873.json
generic🔴 Active Exploitation

curl - connection reuse ignores TLS requirement - CVE-2026-4873

https://curl.se/docs/CVE-2026-4873.html

Vendor Advisories for CVE-2026-4873(2)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(2)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulibcurl4t64 (8.14.1-2ubuntu1.3) @ questing2026-06-27ubuntu
redhatcurl-main-8.20.0-0.1.hum12026-05-02redhat

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.

Additional Vendor Advisories

(1)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 9× in last 7d / 65× 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 132 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-4873?
CVE-2026-4873 is a medium vulnerability published on May 13, 2026. A vulnerability exists where a connection requiring TLS incorrectly reuses an existing unencrypted connection from the same connection pool. If an initial transfer is made in clear-text (via IMAP, SMTP, or POP3), a subsequent request to that same host bypasses the TLS requirement and instead…
When was CVE-2026-4873 disclosed?
CVE-2026-4873 was first published in the National Vulnerability Database on May 13, 2026, with the most recent update on May 14, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-4873 actively exploited?
CVE-2026-4873 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 24.9% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-4873?
CVE-2026-4873 has a CVSS v3 base score of 5.9 (NVD).
How do I remediate CVE-2026-4873?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-4873, 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

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