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
Trending — 4 sources updated this week
5.9EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.9Exploit: None knownExposed: 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)
EG Risk
27(Track)
EG Risk 27/100SSVC: Track

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
Severity59% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
26%
KEV
Not listed

Published

May 13, 2026

Last Modified

September 15, 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 (8.18.0-1ubuntu2.1) @ resolute2026-09-15ubuntu
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.

Affected Packages

(6 across 6 ecosystems)
Alpine:v3.23(1)
PackageVulnerable rangeFixed inDependents
curl—8.20.0-r0—
Alpine:v3.24(1)
PackageVulnerable rangeFixed inDependents
curl—8.20.0-r0—
Debian:11(1)
PackageVulnerable rangeFixed inDependents
curl7.74.0-1.3 ... 8.9.1-2~bpo12+1 (219 versions)——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
curl7.88.1-10 ... 8.9.1-2~bpo12+1 (178 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
curl8.14.1-2, 8.14.1-2+deb13u1, 8.14.1-2+deb13u2, 8.14.1-2+deb13u2~bpo13+1, 8.14.1-2+deb13u38.14.1-2+deb13u4—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
curl8.14.1-2 ... 8.20.0~rc1-1+exp3 (45 versions)8.20.0~rc2-1—

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 / 34× 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 228 total refreshes for this CVE.

  1. 2026-09-18 19:28 UTCEPSS rescore
  2. 2026-09-16 14:08 UTCEPSS rescore
  3. 2026-09-16 05:15 UTCEPSS rescore
  4. 2026-09-15 07:26 UTCVendor advisory
  5. 2026-09-15 07:26 UTCGHSA enrichment
  6. 2026-09-15 06:40 UTCEG score recompute
  7. 2026-09-15 06:40 UTCVendor advisory
  8. 2026-09-15 06:40 UTCGHSA enrichment
  9. 2026-09-13 16:47 UTCEPSS rescore
  10. 2026-09-11 14:53 UTCEPSS rescore
  11. 2026-09-11 09:53 UTCOSV refresh
  12. 2026-09-10 09:35 UTCEPSS rescore
  13. 2026-09-08 22:01 UTCEPSS rescore
  14. 2026-09-07 16:01 UTCEPSS rescore
  15. 2026-09-06 13:47 UTCEPSS rescore
  16. 2026-09-04 05:06 UTCEPSS rescore
  17. 2026-09-02 14:12 UTCEPSS rescore
  18. 2026-09-01 13:54 UTCEPSS rescore
  19. 2026-09-01 04:40 UTCEPSS rescore
  20. 2026-08-30 19:17 UTCEPSS rescore
  21. 2026-08-30 01:22 UTCEPSS rescore
  22. 2026-08-28 21:41 UTCEPSS rescore
  23. 2026-08-27 14:25 UTCEPSS rescore
  24. 2026-08-26 14:46 UTCEPSS rescore
  25. 2026-08-25 13:49 UTCEPSS rescore
Show 75 more
  1. 2026-08-23 17:58 UTCEG score recompute
  2. 2026-08-23 17:58 UTCVendor advisory
  3. 2026-08-23 17:58 UTCGHSA enrichment
  4. 2026-08-23 00:19 UTCEPSS rescore
  5. 2026-08-21 23:49 UTCEPSS rescore
  6. 2026-08-20 22:55 UTCEPSS rescore
  7. 2026-08-20 21:33 UTCEG score recompute
  8. 2026-08-20 21:33 UTCVendor advisory
  9. 2026-08-20 21:33 UTCGHSA enrichment
  10. 2026-08-19 17:04 UTCEPSS rescore
  11. 2026-08-18 13:48 UTCEPSS rescore
  12. 2026-08-17 13:47 UTCEPSS rescore
  13. 2026-08-17 10:44 UTCEG score recompute
  14. 2026-08-17 10:44 UTCVendor advisory
  15. 2026-08-17 10:44 UTCGHSA enrichment
  16. 2026-08-16 14:56 UTCEPSS rescore
  17. 2026-08-16 04:08 UTCEG score recompute
  18. 2026-08-16 04:08 UTCVendor advisory
  19. 2026-08-16 04:08 UTCGHSA enrichment
  20. 2026-08-16 02:14 UTCEPSS rescore
  21. 2026-08-15 01:30 UTCEPSS rescore
  22. 2026-08-14 02:36 UTCEG score recompute
  23. 2026-08-14 02:36 UTCVendor advisory
  24. 2026-08-14 02:36 UTCGHSA enrichment
  25. 2026-08-13 22:00 UTCEPSS rescore
  26. 2026-08-12 15:54 UTCEG score recompute
  27. 2026-08-12 15:54 UTCVendor advisory
  28. 2026-08-12 15:54 UTCGHSA enrichment
  29. 2026-08-12 13:51 UTCEPSS rescore
  30. 2026-08-11 07:17 UTCEG score recompute
  31. 2026-08-11 07:17 UTCVendor advisory
  32. 2026-08-11 07:17 UTCGHSA enrichment
  33. 2026-08-11 00:00 UTCEPSS rescore
  34. 2026-08-10 05:49 UTCEG score recompute
  35. 2026-08-10 05:49 UTCVendor advisory
  36. 2026-08-10 05:49 UTCGHSA enrichment
  37. 2026-08-09 13:46 UTCEPSS rescore
  38. 2026-08-09 04:21 UTCEG score recompute
  39. 2026-08-09 04:21 UTCVendor advisory
  40. 2026-08-09 04:21 UTCGHSA enrichment
  41. 2026-08-08 16:37 UTCEPSS rescore
  42. 2026-08-08 02:53 UTCEG score recompute
  43. 2026-08-08 02:53 UTCVendor advisory
  44. 2026-08-08 02:53 UTCGHSA enrichment
  45. 2026-08-07 01:25 UTCEG score recompute
  46. 2026-08-07 01:25 UTCVendor advisory
  47. 2026-08-07 01:25 UTCGHSA enrichment
  48. 2026-08-06 13:47 UTCEPSS rescore
  49. 2026-08-05 21:43 UTCEG score recompute
  50. 2026-08-05 21:43 UTCVendor advisory
  51. 2026-08-05 21:43 UTCGHSA enrichment
  52. 2026-08-05 19:17 UTCEPSS rescore
  53. 2026-08-04 15:10 UTCEPSS rescore
  54. 2026-08-04 10:39 UTCEPSS rescore
  55. 2026-08-04 00:11 UTCEG score recompute
  56. 2026-08-04 00:11 UTCVendor advisory
  57. 2026-08-04 00:11 UTCGHSA enrichment
  58. 2026-08-03 10:36 UTCEPSS rescore
  59. 2026-08-02 22:43 UTCEG score recompute
  60. 2026-08-02 22:43 UTCVendor advisory
  61. 2026-08-02 22:43 UTCGHSA enrichment
  62. 2026-08-02 02:27 UTCEPSS rescore
  63. 2026-08-01 21:15 UTCEG score recompute
  64. 2026-08-01 21:15 UTCVendor advisory
  65. 2026-08-01 21:14 UTCGHSA enrichment
  66. 2026-08-01 04:16 UTCEPSS rescore
  67. 2026-07-30 16:28 UTCEPSS rescore
  68. 2026-07-30 01:30 UTCEPSS rescore
  69. 2026-07-28 15:37 UTCEPSS rescore
  70. 2026-07-26 14:54 UTCEPSS rescore
  71. 2026-07-25 14:18 UTCEPSS rescore
  72. 2026-07-24 14:18 UTCEPSS rescore
  73. 2026-07-23 14:18 UTCEPSS rescore
  74. 2026-07-23 03:18 UTCEG score recompute
  75. 2026-07-22 14:08 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 September 15, 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 0% probability of exploitation in the next 30 days, which ranks it in the top 73.8% of all scored CVEs.
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

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-4873

Explore →

Is Your Infrastructure Affected by CVE-2026-4873?

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

Start Free Scan →Browse All CVEs