curl libcurl up to 8.22.0 insertion of sensitive information into sent data

CVSS Meta Temp Score
CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.
Current Exploit Price (≈)
Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.
CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
5.3$0-$5k1.99-

Summaryinfo

A vulnerability was found in curl libcurl. It has been rated as problematic. This impacts an unknown function. Performing a manipulation results in insertion of sensitive information into sent data. This vulnerability was named CVE-2026-86414. The attack may be initiated remotely. There is no available exploit.

Detailsinfo

A vulnerability, which was classified as problematic, was found in curl libcurl. This affects an unknown function. The manipulation with an unknown input leads to a insertion of sensitive information into sent data vulnerability. CWE is classifying the issue as CWE-201. The code transmits data to another actor, but a portion of the data includes sensitive information that should not be accessible to that actor. This is going to have an impact on confidentiality. The summary by CVE is:

An HTTP proxy can trick libcurl into sending the origin's credentials (Basic password, or a Negotiate/Kerberos ticket) to the proxy itself, by answering the `CONNECT` tunnel request with 401 `WWW-Authenticate:` instead of the expected 407 `Proxy-Authenticate:`.

It is possible to read the advisory at curl.se. This vulnerability is uniquely identified as CVE-2026-86414 since 09/07/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 10/20/2026). The attack technique deployed by this issue is T1592 according to MITRE ATT&CK.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

Vendor

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.3
VulDB Meta Temp Score: 5.3

VulDB Base Score: 5.3
VulDB Temp Score: 5.3
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Insertion of sensitive information into sent data
CWE: CWE-201 / CWE-200 / CWE-284
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

09/07/2026 CVE reserved
10/20/2026 +43 days Advisory disclosed
10/20/2026 +0 days VulDB entry created
10/20/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: curl.se
Status: Confirmed

CVE: CVE-2026-86414 (🔒)
GCVE (CVE): GCVE-0-2026-86414
GCVE (VulDB): GCVE-100-423003

Entryinfo

Created: 10/20/2026 22:48
Changes: 10/20/2026 22:48 (52)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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