---
schema_version: '1.0'
id: security-20260705-f05b21
url: https://osv.dev/vulnerability/CVE-2026-1965
url_hash: f05b21fa4d9bfbb6f4a91c7400cdc342d9ce5af17ad11bab3e0c2b431b5c4d8c
canonical_url: https://osv.dev/vulnerability/CVE-2026-1965
source: osv:nvd
category: security/library
category_raw: cve/library
region: null
tags:
- cve
- CVE-2026-1965
- severity:CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
- https://github.com/curl/curl
- GIT
lang: en
published_at: '2026-03-11T11:15:59Z'
fetched_at: '2026-07-05T15:34:34Z'
updated_at: '2026-07-08T15:37:33Z'
status: published
content_hash: d8f883eb36650e8e2d1400c30e16b349fadd10621b0a8b86474ff1682a9e311b
license_note: full
summary: bad reuse of HTTP Negotiate connection
summary_source: rss
summary_en: bad reuse of HTTP Negotiate connection
entities:
- name: CVE-2013-0074
  type: naturalobject
- name: GitHub
  type: organization
- name: HTTPクライアント型エージェント
  type: UNKNOWN
- name: ConnectionPooler
  type: concept
related_auto:
- name: agent_openclaw
  type: person
  weight: 1.0
- name: CVSS score
  type: concept
  weight: 1.0
- name: AI Agent
  type: artifact
  weight: 1.0
- name: Hy3
  type: artifact
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- name: OpenClaw
  type: artifact
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title: CVE-2026-1965 — https://github.com/curl/curl
---

# CVE-2026-1965: bad reuse of HTTP Negotiate connection

## TL;DR
bad reuse of HTTP Negotiate connection

## Key Points
- cve / CVE-2026-1965 / severity:CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N / https://github.com/curl/curl / GIT

## Details
**Severity:** CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
**Advisory:** CVE-2026-1965

**Affected (your watchlist):**
- `GIT:https://github.com/curl/curl` curl-8_9_1 → no fixed version listed [mac]

**Details:**
libcurl can in some circumstances reuse the wrong connection when asked to do
an Negotiate-authenticated HTTP or HTTPS request.

libcurl features a pool of recent connections so that subsequent requests can
reuse an existing connection to avoid overhead.

When reusing a connection a range of criterion must first be met. Due to a
logical error in the code, a request that was issued by an application could
wrongfully reuse an existing connection to the same server that was
authenticated using different credentials. One underlying reason being that
Negotiate sometimes authenticates *connections* and not *requests*, contrary
to how HTTP is designed to work.

An application that allows Negotiate authentication to a server (that responds
wanting Negotiate) with `user1:password1` and then does another operation to
the same server also using Negotiate but with `user2:password2` (while the
previous connection is still alive) - the second request wrongly reused the
same connection and since it then sees that the Negotiate negotiation is
already made, it just sends the request over that connection thinking it uses
the user2 credentials when it is in fact still using the connection
authenticated for user1...

The set of authentication methods to use is set with  `CURLOPT_HTTPAUTH`.

Applications can disable libcurl's reuse of connections and thus mitigate this
problem, by using one of the following libcurl options to alter how
connections are or are not reused: `CURLOPT_FRESH_CONNECT`,
`CURLOPT_MAXCONNECTS` and `CURLMOPT_MAX_HOST_CONNECTIONS` (if using the
curl_multi API).

**References:**
- https://curl.se/docs/CVE-2026-1965.html
- https://curl.se/docs/CVE-2026-1965.json
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/1xxx/CVE-2026-1965.json
- https://nvd.nist.gov/vuln/detail/CVE-2026-1965

_Data: OSV.dev (upstream: nvd) — https://osv.dev/vulnerability/CVE-2026-1965_

## Source
元記事: [CVE-2026-1965: bad reuse of HTTP Negotiate connection](https://osv.dev/vulnerability/CVE-2026-1965) — published 2026-03-11T11:15:59Z