---
id: CVE-2026-107929
title: local interface connection reuse mixup
summary: |-
  When `CURLOPT_INTERFACE` (or the command line tool's `--interface` option) is
  set with one of the documented prefixes (`if!`, `host!`, `ifhost!`), that
  binding is not part of the connection reuse key, so a later transfer asking
  for a dif…
severity: none
cwe:
  - CWE-488
vendor: curl
product: curl
affected:
  - curl >= 8.22.0 <= 8.22.0
  - curl >= 8.21.0 <= 8.21.0
  - curl >= 8.20.0 <= 8.20.0
  - curl >= 8.19.0 <= 8.19.0
  - curl >= 8.18.0 <= 8.18.0
  - curl >= 8.17.0 <= 8.17.0
  - curl >= 8.16.0 <= 8.16.0
  - curl >= 8.15.0 <= 8.15.0
  - curl >= 8.14.1 <= 8.14.1
  - curl >= 8.14.0 <= 8.14.0
  - curl >= 8.13.0 <= 8.13.0
  - curl >= 8.12.1 <= 8.12.1
  - curl >= 8.12.0 <= 8.12.0
  - curl >= 8.11.1 <= 8.11.1
  - curl >= 8.11.0 <= 8.11.0
  - curl >= 8.10.1 <= 8.10.1
  - curl >= 8.10.0 <= 8.10.0
  - curl >= 8.9.1 <= 8.9.1
  - curl >= 8.9.0 <= 8.9.0
published: '2026-10-20'
updated: '2026-10-20'
sourceUpdated: '2026-10-20T20:29:28.177Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-107929'
references:
  - url: 'https://curl.se/docs/CVE-2026-107929.json'
    label: json
  - url: 'https://curl.se/docs/CVE-2026-107929.html'
    label: www
  - url: 'https://hackerone.com/reports/4099618'
    label: issue
tags:
  - cve.org
ingestedAt: '2026-10-20T21:19:21.269Z'
---

## Overview

When `CURLOPT_INTERFACE` (or the command line tool's `--interface` option) is
set with one of the documented prefixes (`if!`, `host!`, `ifhost!`), that
binding is not part of the connection reuse key, so a later transfer asking
for a different source can silently reuse an existing connection and go out
from the earlier transfer's source address

## Affected

- `curl >= 8.22.0 <= 8.22.0`
- `curl >= 8.21.0 <= 8.21.0`
- `curl >= 8.20.0 <= 8.20.0`
- `curl >= 8.19.0 <= 8.19.0`
- `curl >= 8.18.0 <= 8.18.0`
- `curl >= 8.17.0 <= 8.17.0`
- `curl >= 8.16.0 <= 8.16.0`
- `curl >= 8.15.0 <= 8.15.0`
- `curl >= 8.14.1 <= 8.14.1`
- `curl >= 8.14.0 <= 8.14.0`
- `curl >= 8.13.0 <= 8.13.0`
- `curl >= 8.12.1 <= 8.12.1`
- `curl >= 8.12.0 <= 8.12.0`
- `curl >= 8.11.1 <= 8.11.1`
- `curl >= 8.11.0 <= 8.11.0`
- `curl >= 8.10.1 <= 8.10.1`
- `curl >= 8.10.0 <= 8.10.0`
- `curl >= 8.9.1 <= 8.9.1`
- `curl >= 8.9.0 <= 8.9.0`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.