CVE-2026-107929

local interface connection reuse mixup

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Published Oct 20, 2026 CVSS 3.1 · 8.1 High EPSS < 1% KEV · Not listed
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

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Ubuntu USN Ubuntu USN USN-8927-1 curl vulnerabilities
Ubuntu USN Ubuntu USN USN-8927-2 curl vulnerabilities
History
Type Values Removed Values Added
Metrics cvssV3_1

{'score': 3.7, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N'}

 ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}

cvssV3_1

{'score': 8.1, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H'}
Type Values Removed Values Added
Description A flaw was found in curl. When connection pooling is used with forced local interface binding options, curl fails to include the source interface configuration in its connection reuse cache. An attacker able to initiate network requests in an application using pooled connections can cause subsequent transfers to inadvertently reuse an existing connection. This behavior causes outbound network traffic to be transmitted through the wrong source address, potentially routing requests through an unintended network interface. 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
Title curl: curl: local interface connection reuse mixup local interface connection reuse mixup
References
Type Values Removed Values Added
First Time appeared Curl
Curl curl
Vendors & Products Curl
Curl curl
Type Values Removed Values Added
Description A flaw was found in curl. When connection pooling is used with forced local interface binding options, curl fails to include the source interface configuration in its connection reuse cache. An attacker able to initiate network requests in an application using pooled connections can cause subsequent transfers to inadvertently reuse an existing connection. This behavior causes outbound network traffic to be transmitted through the wrong source address, potentially routing requests through an unintended network interface.
Title curl: curl: local interface connection reuse mixup
Weaknesses CWE-488
References
Metrics threat_severity

None

 cvssV3_1

{'score': 3.7, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N'}

threat_severity

Low
Weaknesses

Sources

Status
PUBLISHED
Assigner
curl
Published
Updated
Oct 30, 2026, 4:31 PM
Reserved
Oct 9, 2026, 7:51 AM

View source JSON

Updated
Oct 30, 2026, 4:30 PM

JSON

Status
Awaiting Analysis
Published
Oct 20, 2026, 9:17 PM
Modified
Oct 30, 2026, 5:17 PM

View source JSON

Severity
Low
Public date
Oct 14, 2026, 12:00 PM

View source Bugzilla JSON

Updated
Oct 30, 2026, 7:00 PM

JSON