connection reuse ignores TLS requirement
Summary
| CVE | CVE-2026-4873 |
|---|---|
| State | PUBLISHED |
| Assigner | curl |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-05-13 13:01:55 UTC |
| Updated | 2026-09-15 07:16:28 UTC |
| Description | 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. |
Risk And Classification
Primary CVSS: v3.1 5.9 MEDIUM from ADP
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
EPSS: 0.000180000 probability, percentile 0.048890000 (date 2026-05-21)
Problem Types: CWE-319 | CWE-295 | CWE-319 Cleartext Transmission of Sensitive Information | CWE-319 CWE-319 Cleartext Transmission of Sensitive Information
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | ADP | DECLARED | 5.9 | MEDIUM | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N |
| 3.1 | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | Secondary | 5.9 | MEDIUM | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
HighPrivileges Required
NoneUser Interaction
NoneScope
UnchangedConfidentiality
HighIntegrity
NoneAvailability
NoneCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD Known Affected Configurations (CPE 2.3)
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Curl | Curl | affected 7.20.0 8.14.2 semver | Not specified |
| CNA | Curl | Curl | affected 8.15.0 8.16.1 semver | Not specified |
| CNA | Curl | Curl | affected 8.17.0 8.20.0 semver | Not specified |
| CNA | Curl | Curl | affected ec3bb8f727405642a471b4b1b9eb0118fc003104 507e7be573b0a76fca597b75ff7cb27a66e7d865 git | Not specified |
| CNA | Curl | Curl | affected 8.19.0 | Not specified |
| CNA | Curl | Curl | affected 8.18.0 | Not specified |
| CNA | Curl | Curl | affected 8.17.0 | Not specified |
| CNA | Curl | Curl | affected 8.16.0 | Not specified |
| CNA | Curl | Curl | affected 8.15.0 | Not specified |
| CNA | Curl | Curl | affected 8.14.1 | Not specified |
| CNA | Curl | Curl | affected 8.14.0 | Not specified |
| CNA | Curl | Curl | affected 8.13.0 | Not specified |
| CNA | Curl | Curl | affected 8.12.1 | Not specified |
| CNA | Curl | Curl | affected 8.12.0 | Not specified |
| CNA | Curl | Curl | affected 8.11.1 | Not specified |
| CNA | Curl | Curl | affected 8.11.0 | Not specified |
| CNA | Curl | Curl | affected 8.10.1 | Not specified |
| CNA | Curl | Curl | affected 8.10.0 | Not specified |
| CNA | Curl | Curl | affected 8.9.1 | Not specified |
| CNA | Curl | Curl | affected 8.9.0 | Not specified |
| CNA | Curl | Curl | affected 8.8.0 | Not specified |
| CNA | Curl | Curl | affected 8.7.1 | Not specified |
| CNA | Curl | Curl | affected 8.7.0 | Not specified |
| CNA | Curl | Curl | affected 8.6.0 | Not specified |
| CNA | Curl | Curl | affected 8.5.0 | Not specified |
| CNA | Curl | Curl | affected 8.4.0 | Not specified |
| CNA | Curl | Curl | affected 8.3.0 | Not specified |
| CNA | Curl | Curl | affected 8.2.1 | Not specified |
| CNA | Curl | Curl | affected 8.2.0 | Not specified |
| CNA | Curl | Curl | affected 8.1.2 | Not specified |
| CNA | Curl | Curl | affected 8.1.1 | Not specified |
| CNA | Curl | Curl | affected 8.1.0 | Not specified |
| CNA | Curl | Curl | affected 8.0.1 | Not specified |
| CNA | Curl | Curl | affected 8.0.0 | Not specified |
| CNA | Curl | Curl | affected 7.88.1 | Not specified |
| CNA | Curl | Curl | affected 7.88.0 | Not specified |
| CNA | Curl | Curl | affected 7.87.0 | Not specified |
| CNA | Curl | Curl | affected 7.86.0 | Not specified |
| CNA | Curl | Curl | affected 7.85.0 | Not specified |
| CNA | Curl | Curl | affected 7.84.0 | Not specified |
| CNA | Curl | Curl | affected 7.83.1 | Not specified |
| CNA | Curl | Curl | affected 7.83.0 | Not specified |
| CNA | Curl | Curl | affected 7.82.0 | Not specified |
| CNA | Curl | Curl | affected 7.81.0 | Not specified |
| CNA | Curl | Curl | affected 7.80.0 | Not specified |
| CNA | Curl | Curl | affected 7.79.1 | Not specified |
| CNA | Curl | Curl | affected 7.79.0 | Not specified |
| CNA | Curl | Curl | affected 7.78.0 | Not specified |
| CNA | Curl | Curl | affected 7.77.0 | Not specified |
| CNA | Curl | Curl | affected 7.76.1 | Not specified |
| CNA | Curl | Curl | affected 7.76.0 | Not specified |
| CNA | Curl | Curl | affected 7.75.0 | Not specified |
| CNA | Curl | Curl | affected 7.74.0 | Not specified |
| CNA | Curl | Curl | affected 7.73.0 | Not specified |
| CNA | Curl | Curl | affected 7.72.0 | Not specified |
| CNA | Curl | Curl | affected 7.71.1 | Not specified |
| CNA | Curl | Curl | affected 7.71.0 | Not specified |
| CNA | Curl | Curl | affected 7.70.0 | Not specified |
| CNA | Curl | Curl | affected 7.69.1 | Not specified |
| CNA | Curl | Curl | affected 7.69.0 | Not specified |
| CNA | Curl | Curl | affected 7.68.0 | Not specified |
| CNA | Curl | Curl | affected 7.67.0 | Not specified |
| CNA | Curl | Curl | affected 7.66.0 | Not specified |
| CNA | Curl | Curl | affected 7.65.3 | Not specified |
| CNA | Curl | Curl | affected 7.65.2 | Not specified |
| CNA | Curl | Curl | affected 7.65.1 | Not specified |
| CNA | Curl | Curl | affected 7.65.0 | Not specified |
| CNA | Curl | Curl | affected 7.64.1 | Not specified |
| CNA | Curl | Curl | affected 7.64.0 | Not specified |
| CNA | Curl | Curl | affected 7.63.0 | Not specified |
| CNA | Curl | Curl | affected 7.62.0 | Not specified |
| CNA | Curl | Curl | affected 7.61.1 | Not specified |
| CNA | Curl | Curl | affected 7.61.0 | Not specified |
| CNA | Curl | Curl | affected 7.60.0 | Not specified |
| CNA | Curl | Curl | affected 7.59.0 | Not specified |
| CNA | Curl | Curl | affected 7.58.0 | Not specified |
| CNA | Curl | Curl | affected 7.57.0 | Not specified |
| CNA | Curl | Curl | affected 7.56.1 | Not specified |
| CNA | Curl | Curl | affected 7.56.0 | Not specified |
| CNA | Curl | Curl | affected 7.55.1 | Not specified |
| CNA | Curl | Curl | affected 7.55.0 | Not specified |
| CNA | Curl | Curl | affected 7.54.1 | Not specified |
| CNA | Curl | Curl | affected 7.54.0 | Not specified |
| CNA | Curl | Curl | affected 7.53.1 | Not specified |
| CNA | Curl | Curl | affected 7.53.0 | Not specified |
| CNA | Curl | Curl | affected 7.52.1 | Not specified |
| CNA | Curl | Curl | affected 7.52.0 | Not specified |
| CNA | Curl | Curl | affected 7.51.0 | Not specified |
| CNA | Curl | Curl | affected 7.50.3 | Not specified |
| CNA | Curl | Curl | affected 7.50.2 | Not specified |
| CNA | Curl | Curl | affected 7.50.1 | Not specified |
| CNA | Curl | Curl | affected 7.50.0 | Not specified |
| CNA | Curl | Curl | affected 7.49.1 | Not specified |
| CNA | Curl | Curl | affected 7.49.0 | Not specified |
| CNA | Curl | Curl | affected 7.48.0 | Not specified |
| CNA | Curl | Curl | affected 7.47.1 | Not specified |
| CNA | Curl | Curl | affected 7.47.0 | Not specified |
| CNA | Curl | Curl | affected 7.46.0 | Not specified |
| CNA | Curl | Curl | affected 7.45.0 | Not specified |
| CNA | Curl | Curl | affected 7.44.0 | Not specified |
| CNA | Curl | Curl | affected 7.43.0 | Not specified |
| CNA | Curl | Curl | affected 7.42.1 | Not specified |
| CNA | Curl | Curl | affected 7.42.0 | Not specified |
| CNA | Curl | Curl | affected 7.41.0 | Not specified |
| CNA | Curl | Curl | affected 7.40.0 | Not specified |
| CNA | Curl | Curl | affected 7.39.0 | Not specified |
| CNA | Curl | Curl | affected 7.38.0 | Not specified |
| CNA | Curl | Curl | affected 7.37.1 | Not specified |
| CNA | Curl | Curl | affected 7.37.0 | Not specified |
| CNA | Curl | Curl | affected 7.36.0 | Not specified |
| CNA | Curl | Curl | affected 7.35.0 | Not specified |
| CNA | Curl | Curl | affected 7.34.0 | Not specified |
| CNA | Curl | Curl | affected 7.33.0 | Not specified |
| CNA | Curl | Curl | affected 7.32.0 | Not specified |
| CNA | Curl | Curl | affected 7.31.0 | Not specified |
| CNA | Curl | Curl | affected 7.30.0 | Not specified |
| CNA | Curl | Curl | affected 7.29.0 | Not specified |
| CNA | Curl | Curl | affected 7.28.1 | Not specified |
| CNA | Curl | Curl | affected 7.28.0 | Not specified |
| CNA | Curl | Curl | affected 7.27.0 | Not specified |
| CNA | Curl | Curl | affected 7.26.0 | Not specified |
| CNA | Curl | Curl | affected 7.25.0 | Not specified |
| CNA | Curl | Curl | affected 7.24.0 | Not specified |
| CNA | Curl | Curl | affected 7.23.1 | Not specified |
| CNA | Curl | Curl | affected 7.23.0 | Not specified |
| CNA | Curl | Curl | affected 7.22.0 | Not specified |
| CNA | Curl | Curl | affected 7.21.7 | Not specified |
| CNA | Curl | Curl | affected 7.21.6 | Not specified |
| CNA | Curl | Curl | affected 7.21.5 | Not specified |
| CNA | Curl | Curl | affected 7.21.4 | Not specified |
| CNA | Curl | Curl | affected 7.21.3 | Not specified |
| CNA | Curl | Curl | affected 7.21.2 | Not specified |
| CNA | Curl | Curl | affected 7.21.1 | Not specified |
| CNA | Curl | Curl | affected 7.21.0 | Not specified |
| CNA | Curl | Curl | affected 7.20.1 | Not specified |
| CNA | Curl | Curl | affected 7.20.0 | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| curl.se/docs/CVE-2026-4873.html | 2499f714-1537-4658-8207-48ae4bb9eae9 | curl.se | Patch, Vendor Advisory |
| curl.se/docs/CVE-2026-4873.json | 2499f714-1537-4658-8207-48ae4bb9eae9 | curl.se | Vendor Advisory |
| www.openwall.com/lists/oss-security/2026/04/29/7 | af854a3a-2127-422b-91ae-364da2661108 | www.openwall.com | Mailing List, Patch, Third Party Advisory |
| hackerone.com/reports/3621851 | 2499f714-1537-4658-8207-48ae4bb9eae9 | hackerone.com | Exploit, Issue Tracking, Third Party Advisory |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Arkadi Vainbrand (en)
CNA: Daniel Stenberg (en)
There are currently no legacy QID mappings associated with this CVE.