CVE-2026-19931
criticalA flaw in libcurl makes it wrongly reuse an HTTP connection setup for a given hostname using Negotiate authentication, when the initial request is done using e…
Vendor / product: Haxx — curl
A flaw in libcurl makes it wrongly reuse an HTTP connection setup for a given hostname using Negotiate authentication, when the initial request is done using empty credentials. This can make user B's request get sent over user A's previously authenticated connection.
CVSS
9.8
9.8 (CVSS v3.1)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Severity source: NVD CVSS v3.1 (134c704f-9b21-4f2e-91b3-4a467353bcc0)
Timeline (UTC)
Published: 2026-09-06 18:17
Modified: 2026-09-15 07:16
NVD status: Modified
Last synced 1 day ago
Verified against the source API 2026-10-27 06:50 UTC
Exploitation
Not listed in CISA KEV (as of last catalog sync)
Absence from KEV does not mean a CVE is not exploited. Exploitation status: unknown (no authoritative evidence in our sources).
Affected products
haxx / curl ≥7.64.1 <8.22.0
Weakness classification (CWE)
Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.
Mitigation & advisories
Vendor advisory: https://curl.se/docs/CVE-2026-19931.html
Vendor advisory: https://curl.se/docs/CVE-2026-19931.json
Patch / mitigation: https://curl.se/docs/CVE-2026-19931.html
Patch / mitigation: https://hackerone.com/reports/3923520
Patch / mitigation: https://hackerone.com/reports/3923520
References
- https://curl.se/docs/CVE-2026-19931.html 2499f714-1537-4658-8207-48ae4bb9eae9
- https://curl.se/docs/CVE-2026-19931.json 2499f714-1537-4658-8207-48ae4bb9eae9
- https://hackerone.com/reports/3923520 2499f714-1537-4658-8207-48ae4bb9eae9
- https://hackerone.com/reports/3923520 134c704f-9b21-4f2e-91b3-4a467353bcc0
Data sources
NVD CVE API 2.0 — fetched 2026-10-27 06:50 UTC · record ↗