CVE-2026-32145: Multipart form body parser bypasses body size limits in wisp

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-04-02 · updated 2026-10-26
Weakness: CWE-770

Description

Allocation of Resources Without Limits or Throttling vulnerability in gleam-wisp wisp allows a denial of service via multipart form body parsing. The multipart_body function bypasses configured max_body_size and max_files_size limits. When a multipart boundary is not present in a chunk, the parser takes the MoreRequiredForBody path, which appends the chunk to the output but passes the quota unchanged to the recursive call. Only the final chunk containing the boundary is counted via decrement_quota. The same pattern exists in multipart_headers, where MoreRequiredForHeaders recurses without calling decrement_body_quota. An unauthenticated attacker can exhaust server memory or disk by sending arbitrarily large multipart form submissions in a single HTTP request. This issue affects wisp: from 0.2.0 before 2.2.2.

Affected products

gleam-wisp wisp: from 0.2.0 before 2.2.2 — fixed in 2.2.2

How to fix

Upgrade to a fixed version: gleam-wisp wisp 2.2.2. Check the vendor advisory for mitigations.

References

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