CVE-2026-8286

wrong STARTTLS connection reuse

HIGH

8.1

CVSS Score

Published: July 3, 2026 at 06:14 AM UTC

Updated: September 15, 2026 at 07:35 AM UTC

1 product affected across 1 vendorCurl

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Severity

HIGH8.1

Exploit prediction

EPSS 0.3%

SSVC

PoC

Description

A vulnerability exists where a new transfer that uses STARTTLS to upgrade the connection might reuse an existing live connection even though the TLS configuration mismatches so it should not.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Curl · Haxx

95%

7.30.0 ≤ v < 8.14.27.30.0 ≤ v < 8.21.08.15.0 ≤ v < 8.16.18.17.0 ≤ v < 8.20.17.30.0 7.31.0 7.32.0 7.33.0 7.34.0 7.35.0 7.36.0 7.37.0 7.37.1 7.38.0 7.39.0 7.40.0 7.41.0 7.42.0 7.42.1 7.43.0 7.44.0 7.45.0 7.46.0 7.47.0 7.47.1 7.48.0 7.49.0 7.49.1 7.50.0 7.50.1 7.50.2 7.50.3 7.51.0 7.52.0 7.52.1 7.53.0 7.53.1 7.54.0 7.54.1 7.55.0 7.55.1 7.56.0 7.56.1 7.57.0 7.58.0 7.59.0 7.60.0 7.61.0 7.61.1 7.62.0 7.63.0 7.64.0 7.64.1 7.65.0 7.65.1 7.65.2 7.65.3 7.66.0 7.67.0 7.68.0 7.69.0 7.69.1 7.70.0 7.71.0 7.71.1 7.72.0 7.73.0 7.74.0 7.75.0 7.76.0 7.76.1 7.77.0 7.78.0 7.79.0 7.79.1 7.80.0 7.81.0 7.82.0 7.83.0 7.83.1 7.84.0 7.85.0 7.86.0 7.87.0 7.88.0 7.88.1 8.0.0 8.0.1 8.1.0 8.1.1 8.1.2 8.10.0 8.10.1 8.11.0 8.11.1 8.12.0 8.12.1 8.13.0 8.14.0 8.14.1 8.15.0 8.16.0 8.17.0 8.18.0 8.19.0 8.2.0 8.2.1 8.20.0 8.3.0 8.4.0 8.5.0 8.6.0 8.7.0 8.7.1 8.8.0 8.9.0 8.9.1a1701eea289fe7ea80651f801cf992838a491dde

Vendor states this is fixed in a86efdd7ca5433de9231e650f18247de8319ad16 (fixed)

Affected range stops below 8.14.2, so it looks safe — our inference, not a vendor statement

Affected range stops below 8.16.1, so it looks safe — our inference, not a vendor statement

Affected range stops below 8.20.1, so it looks safe — our inference, not a vendor statement

Affected range stops below 8.21.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

References (3)

Vendor Advisory

Source: cverecord

https://curl.se/docs/CVE-2026-8286.json

PatchVendor Advisory

Source: cverecord

https://curl.se/docs/CVE-2026-8286.html

ExploitIssue TrackingThird Party Advisory

Source: cverecord

https://hackerone.com/reports/3718195

SSVC — Action Prioritization

SSVCPoCNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.1HIGHCISA-ADP

Attack Vector: NETWORK
Complexity: LOW
Privileges: LOW
User Interaction: NONE
Scope: UNCHANGED
Confidentiality: HIGH
Integrity: HIGH
Availability: NONE

Vector?

Quick Info

StatusMODIFIED

CWE

CWE-295

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