CVE-2026-107929
Received Received - Intake

libcurl Improper Connection Reuse via Interface Binding

Vulnerability report for CVE-2026-107929, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-10-20

Last updated on: 2026-10-20

Assigner: curl

Description

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

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Meta Information

Published
2026-10-20
Last Modified
2026-10-20
Generated
2026-10-21
AI Q&A
2026-10-21
EPSS Evaluated
N/A
NVD

Affected Vendors & Products

Showing 19 associated CPEs
Vendor Product Version / Range
curl curl 8.22.0
curl curl 8.21.0
curl curl 8.20.0
curl curl 8.19.0
curl curl 8.18.0
curl curl 8.17.0
curl curl 8.16.0
curl curl 8.15.0
curl curl 8.14.1
curl curl 8.14.0
curl curl 8.13.0
curl curl 8.12.1
curl curl 8.12.0
curl curl 8.11.1
curl curl 8.11.0
curl curl 8.10.1
curl curl 8.10.0
curl curl 8.9.1
curl curl 8.9.0

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in curl occurs when the CURLOPT_INTERFACE option or --interface command line option is set with specific prefixes like if!, host!, or ifhost!. This causes the binding to not be included in the connection reuse key, allowing a later transfer with a different source to silently reuse an existing connection and send data from the earlier transfer's source address.

Impact Analysis

This vulnerability could allow an attacker to send requests from an unintended source IP address, potentially bypassing network restrictions or obscuring the origin of malicious traffic. It may also lead to data leaks if sensitive information is transmitted from an unexpected source address.

Mitigation Strategies

Update curl to the latest version where this issue is patched. Avoid using the --interface option with prefixes like if!, host!, or ifhost! until the update is applied.

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