Summary
wisp has Allocation of Resources Without Limits or Throttling
A multipart form parsing bug allows any unauthenticated user to bypass configured request size limits and trigger a denial of service by exhausting server memory or disk.
Details
The issue is in the multipart parsing logic, specifically in multipart_body and multipart_headers.
When parsing multipart data, the implementation distinguishes between:
- chunks where a boundary is found
- chunks where more data is required
In the normal case (boundary found), the parser correctly accounts for consumed bytes by calling decrement_quota.
However, in the MoreRequiredForBody branch, the parser appends incoming data to the output but recurses without decrementing the quota. This means that any chunk that does not contain the multipart boundary is effectively “free” from a quota perspective. Only the final chunk, the one containing the boundary, is counted.
The same pattern exists in multipart_headers, where MoreRequiredForHeaders also recurses without decrementing the quota.
As a result, an attacker can send arbitrarily large multipart bodies split across many chunks that avoid the boundary. The parser will accumulate the data (in memory for form fields, on disk for file uploads) without enforcing max_body_size or max_files_size.
Workaround
Deploy a reverse proxy (such as nginx or HAProxy) in front of the application and enforce request body size limits there. This ensures large multipart requests are rejected before they reach the vulnerable parser.
Resources
Impact
This is a denial of service vulnerability caused by uncontrolled resource consumption.
Any application using require_form or require_multipart_form on user-controlled input is affected. An unauthenticated attacker can send large multipart requests that bypass configured limits and cause:
- memory exhaustion (for form fields accumulated in memory)
- disk exhaustion (for file uploads written to temporary storage)
In both cases, the application may become unavailable or be terminated by the operating system.
The application allocates resources such as memory, threads, or file descriptors based on untrusted input without enforcing a cap. Typical impact: resource exhaustion leading to denial of service.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2026-32145? CVE-2026-32145 is a high-severity allocation of resources without limits or throttling vulnerability in wisp (erlang), affecting versions < 2.2.2. It is fixed in 2.2.2. The application allocates resources such as memory, threads, or file descriptors based on untrusted input without enforcing a cap.
- Which versions of wisp are affected by CVE-2026-32145? wisp (erlang) versions < 2.2.2 is affected.
- Is there a fix for CVE-2026-32145? Yes. CVE-2026-32145 is fixed in 2.2.2. Upgrade to this version or later.
- Is CVE-2026-32145 exploitable, and should I be worried? Whether CVE-2026-32145 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-32145 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-32145? Upgrade
wispto 2.2.2 or later.