CVE-2026-33752

HighPublic PoC

Published: 06 April 2026

Published

06 April 2026

Modified

09 April 2026

KEV Added

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Patch

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CVSS Score 8.6 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

EPSS Score 0.0001 3.3th percentile

Risk Priority 17 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-33752 is a high-severity SSRF (CWE-918) vulnerability in Lexiforest Curl Cffi. Its CVSS base score is 8.6 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 3.3th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified are NIST 800-53 SC-7 (Boundary Protection) and SI-10 (Information Input Validation).

Threat & Defense at a Glance

What attackers do: exploitation maps to Exploit Public-Facing Application (T1190) and 1 other technique. What defenders deploy: see the NIST 800-53 controls recommended below.

Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

SI-2 Flaw Remediation good match

prevent

Directly remediates the SSRF vulnerability in curl_cffi prior to 0.15.0 by requiring timely identification, reporting, and patching of the flaw.

SI-10 Information Input Validation good match

prevent

Requires validation of attacker-controlled URLs input to curl_cffi to block redirects to internal IP ranges and cloud metadata endpoints.

SC-7 Boundary Protection good match

prevent

Monitors and controls communications at key internal boundaries to prevent unauthorized application access to sensitive internal services like metadata endpoints.

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.

attack.mitre.org →

T1522 Cloud Instance Metadata API Credential Access

Adversaries may attempt to access the Cloud Instance Metadata API to collect credentials and other sensitive data.

attack.mitre.org →

Why these techniques?

SSRF in public-facing app library enables T1190 exploitation; direct access to cloud metadata endpoints facilitates T1522.

Confidence: HIGH · MITRE ATT&CK Enterprise v18.1

NVD Description

curl_cffi is the a Python binding for curl. Prior to 0.15.0, curl_cffi does not restrict requests to internal IP ranges, and follows redirects automatically via the underlying libcurl. Because of this, an attacker-controlled URL can redirect requests to internal services…

such as cloud metadata endpoints. In addition, curl_cffi’s TLS impersonation feature can make these requests appear as legitimate browser traffic, which may bypass certain network controls. This vulnerability is fixed in 0.15.0.

Deeper analysisAI

CVE-2026-33752 is a server-side request forgery vulnerability (CWE-918) in curl_cffi, a Python binding for libcurl, affecting versions prior to 0.15.0. The issue arises because curl_cffi does not restrict HTTP requests to internal IP ranges and automatically follows redirects via the underlying libcurl implementation. This enables redirection from attacker-controlled URLs to sensitive internal services, such as cloud metadata endpoints. Furthermore, curl_cffi's TLS impersonation feature can make these requests mimic legitimate browser traffic, potentially bypassing network security controls.

The vulnerability carries a CVSS v3.1 base score of 8.6 (AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N), indicating exploitation by unauthenticated remote attackers with low complexity and no user interaction. An attacker who controls a URL fetched by an application using vulnerable curl_cffi can trigger redirects to internal resources, achieving high-impact confidentiality breaches through unauthorized data access, such as instance metadata in cloud environments.

The vulnerability is fixed in curl_cffi version 0.15.0. Advisory details are available in the GitHub security advisory at https://github.com/lexiforest/curl_cffi/security/advisories/GHSA-qw2m-4pqf-rmpp, which practitioners should consult for patching guidance and additional context.