CVE-2026-8466: CWE-770 Allocation of Resources Without Limits or Throttling in ninenines cowboy
CVE-2026-8466 is a high-severity vulnerability in the ninenines cowboy HTTP server version 2.0.0. It allows an unauthenticated attacker to cause a denial of service by exploiting the lack of limits on resource allocation during multipart header parsing. The vulnerable function accumulates request bytes into a buffer without an upper bound, leading to memory exhaustion. This can be triggered by sending multipart/form-data requests that never complete the header section, potentially exhausting BEAM memory with only a few concurrent malicious uploads.
AI Analysis
Technical Summary
This vulnerability in ninenines cowboy HTTP server (before version 2.15.0) involves CWE-770: allocation of resources without limits or throttling. The cowboy_req:read_part/3 function accumulates incoming request bytes into a buffer without enforcing an upper bound during multipart header parsing. An attacker can exploit this by sending multipart/form-data requests with incomplete headers, causing the server to consume excessive memory and potentially crash due to BEAM memory exhaustion. The vulnerability is unauthenticated and can lead to denial of service conditions.
Potential Impact
An unauthenticated attacker can cause denial of service by exhausting server memory through specially crafted multipart/form-data requests that never complete the header section. This can lead to server instability or crashes, impacting availability. There are no known exploits in the wild at this time.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or temporary workaround has been documented. Until a patch is available, consider implementing external request size limits or rate limiting multipart/form-data requests at a proxy or firewall level to mitigate potential exploitation.
CVE-2026-8466: CWE-770 Allocation of Resources Without Limits or Throttling in ninenines cowboy
Description
CVE-2026-8466 is a high-severity vulnerability in the ninenines cowboy HTTP server version 2.0.0. It allows an unauthenticated attacker to cause a denial of service by exploiting the lack of limits on resource allocation during multipart header parsing. The vulnerable function accumulates request bytes into a buffer without an upper bound, leading to memory exhaustion. This can be triggered by sending multipart/form-data requests that never complete the header section, potentially exhausting BEAM memory with only a few concurrent malicious uploads.
CVSS v4.0
Score 8.2high
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability in ninenines cowboy HTTP server (before version 2.15.0) involves CWE-770: allocation of resources without limits or throttling. The cowboy_req:read_part/3 function accumulates incoming request bytes into a buffer without enforcing an upper bound during multipart header parsing. An attacker can exploit this by sending multipart/form-data requests with incomplete headers, causing the server to consume excessive memory and potentially crash due to BEAM memory exhaustion. The vulnerability is unauthenticated and can lead to denial of service conditions.
Potential Impact
An unauthenticated attacker can cause denial of service by exhausting server memory through specially crafted multipart/form-data requests that never complete the header section. This can lead to server instability or crashes, impacting availability. There are no known exploits in the wild at this time.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or temporary workaround has been documented. Until a patch is available, consider implementing external request size limits or rate limiting multipart/form-data requests at a proxy or firewall level to mitigate potential exploitation.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- EEF
- Date Reserved
- 2026-05-13T11:44:39.149Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a04c4b8cbff5d8610fad362
Added to database: 05/13/2026, 18:36:40 UTC
Last enriched: 05/27/2026, 21:29:35 UTC
Last updated: 07/31/2026, 19:23:00 UTC
Views: 136
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