ninenines cowboy up to 2.14.x Request Body allocation of resources

CVSS Meta Temp Score
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CTI Interest Score
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5.1$0-$5k0.00

Summaryinfo

A vulnerability was found in ninenines cowboy up to 2.14.x. It has been rated as problematic. The affected element is an unknown function of the component Request Body Handler. Performing a manipulation results in allocation of resources. This vulnerability is cataloged as CVE-2026-8466. It is possible to initiate the attack remotely. There is no exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability classified as problematic has been found in ninenines cowboy up to 2.14.x. This affects an unknown function of the component Request Body Handler. The manipulation with an unknown input leads to a allocation of resources vulnerability. CWE is classifying the issue as CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. This is going to have an impact on availability. The summary by CVE is:

Allocation of Resources Without Limits or Throttling vulnerability in ninenines cowboy allows denial of service via unbounded buffer accumulation in multipart header parsing. cowboy_req:read_part/3 in src/cowboy_req.erl accumulates incoming request bytes into a Buffer binary with no upper-bound check. When cow_multipart:parse_headers/2 returns more or {more, Buffer2}, the function reads up to Length bytes (default 64 KB) from the request body and recurses with the enlarged buffer. There is no equivalent of the byte_size(Acc) > Length guard present in the sibling function read_part_body/4. An unauthenticated attacker can send a multipart/form-data request whose body never yields a complete header section — for example, a body that never contains the advertised boundary delimiter, or one whose header lines never contain \r\n\r\n — and force the server process to accumulate memory linearly with the bytes the protocol layer is willing to deliver. A handful of concurrent such uploads is sufficient to exhaust BEAM memory. This issue affects cowboy from 2.0.0 before 2.15.0.

The weakness was shared by Peter Ullrich. It is possible to read the advisory at cna.erlef.org. This vulnerability is uniquely identified as CVE-2026-8466 since 05/13/2026. 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 attack technique deployed by this issue is T1499 according to MITRE ATT&CK.

The vulnerability scanner Nessus provides a plugin with the ID 316423 (Linux Distros Unpatched Vulnerability : CVE-2026-8466), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 2.15.0 eliminates this vulnerability. Applying the patch 5c6a2061b41bb5771c4659fac7d5a822dca5bafb is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (316423) and EUVD (EUVD-2026-30133). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Vendor

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 5.3
VulDB Meta Temp Score: 5.1

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

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

Exploitinginfo

Class: Allocation of resources
CWE: CWE-770 / CWE-400 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 316423
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2026-8466

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: cowboy 2.15.0
Patch: 5c6a2061b41bb5771c4659fac7d5a822dca5bafb

Timelineinfo

05/13/2026 Advisory disclosed
05/13/2026 +0 days CVE reserved
05/13/2026 +0 days VulDB entry created
05/24/2026 +11 days VulDB entry last update

Sourcesinfo

Advisory: cna.erlef.org
Researcher: Peter Ullrich
Status: Confirmed

CVE: CVE-2026-8466 (🔒)
GCVE (CVE): GCVE-0-2026-8466
GCVE (VulDB): GCVE-100-363699
EUVD: 🔒

Entryinfo

Created: 05/13/2026 21:02
Updated: 05/24/2026 06:25
Changes: 05/13/2026 21:02 (69), 05/13/2026 23:38 (1), 05/24/2026 06:25 (2)
Complete: 🔍
Cache ID: 216::103

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

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