CVE-2026-100350

kin-openapi deepObject query decoding repeatedly compiles an invariant regular expression

Uncontrolled CPU consumption (denial of service). Any service that uses openapi3filter.ValidateRequest (directly or via a router) to validate requests against a spec containing at least one in: query, style: deepObject parameter is affected. An unauthenticated attacker who can reach such an endpoint can send requests with large numbers of junk query keys; each request performs a number of regexp.MustCompile calls proportional to the request's query-key count times the number of deepObject parameters on the route. Because the work is CPU-bound and executed during validation (before any application handler runs), modest request rates can starve the process of CPU and degrade or deny service to legitimate clients. There is no impact to confidentiality or integrity.

Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service. Typical impact: denial of service.

CVE-2026-100350 has a CVSS score of 5.3 (Medium). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.146.0); upgrading removes the vulnerable code path.

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Hoist the invariant regexp out of the per-key loop: compile the ^<param>\[ pattern once per deepObject parameter (before iterating the query keys) and reuse the compiled *regexp.Regexp for every key, mirroring how the package-level deepObjectBracketRE (req_resp_decoder.go:41) is already handled. This makes decode cost independent of the junk-key count. Matching semantics are unchanged (the pattern still derives from the spec parameter name via regexp.QuoteMeta, so it stays panic-safe for any name), and *regexp.Regexp is safe for the reuse.

As a mitigation before upgrading, front affected endpoints with a limit on request/URL size or query-key count (e.g. at a reverse proxy or middleware), which bounds the number of loop iterations an attacker can force.

1. What is CVE-2026-100350? CVE-2026-100350 is a medium-severity uncontrolled resource consumption vulnerability in github.com/getkin/kin-openapi (go), affecting versions >= 0.145.0, < 0.146.0. It is fixed in 0.146.0. Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service.
2. How severe is CVE-2026-100350? CVE-2026-100350 has a CVSS score of 5.3 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of github.com/getkin/kin-openapi are affected by CVE-2026-100350? github.com/getkin/kin-openapi (go) versions >= 0.145.0, < 0.146.0 is affected.
4. Is there a fix for CVE-2026-100350? Yes. CVE-2026-100350 is fixed in 0.146.0. Upgrade to this version or later.
5. Is CVE-2026-100350 exploitable, and should I be worried? Whether CVE-2026-100350 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
6. What actually determines whether CVE-2026-100350 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.
7. How do I fix CVE-2026-100350? Upgrade github.com/getkin/kin-openapi to 0.146.0 or later.

Other vulnerabilities in github.com/getkin/kin-openapi