Vulnerability in github.com/getkin/kin-openapi (CVE-2026-100348)
Summary
Vulnerability in github.com/getkin/kin-openapi (CVE-2026-100348). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 0.145.0 or later.
Original description
The description as published by the source.
The defect
Confirmed at HEAD (f0407d5, v0.144.0). openapi3/loader.go, inside resolveComponent's drill closure (around line 455), the case *SchemaRef branch for pathPart == "additionalProperties" dereferences c.Value.AdditionalProperties with no nil-check on c.Value:
case *SchemaRef:
if pathPart == "additionalProperties" {
if ap := c.Value.AdditionalProperties.Has; ap != nil { // c.Value can be nil here
cursor = *ap
} else {
cursor = c.Value.AdditionalProperties.Schema
}
attempted = true
}
When a $ref fragment drills through .../additionalProperties of a schema whose Value is still nil (a pure, not-yet-resolved $ref, or a self-reference resolved before its own Value is set), c.Value is nil and the .AdditionalProperties access panics.
Input and attacker
A tiny crafted OpenAPI document, one schema, no external refs, no network:
openapi: 3.0.3
info: {title: t, version: "1.0.0"}
paths: {}
components:
schemas:
A:
$ref: '#/components/schemas/A/additionalProperties'
Attacker model: any service or tool that loads an untrusted spec via the default openapi3.Loader (LoadFromData / LoadFromFile / LoadFromURI), e.g. a spec registry, an API-management platform ingesting user specs, a linter, or a converter. It crashes during LOAD (ResolveRefsIn), before Validate.
Verification level
EXECUTED with…
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-100348 has been found in github.com/getkin/kin-openapi.
Risk of unauthorized operations or information disclosure. CVSS score: 5.3/10.
What to do: upgrade github.com/getkin/kin-openapi to 0.145.0 or later.
If unsure, ask your IT team or search "github.com/getkin/kin-openapi CVE-2026-100348" on the vendor's site.
CVE-2026-100348 (github.com/getkin/kin-openapi) — CWE-476 / CVSS v3 5.3
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Patched: 0.145.0 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-476) exists in github.com/getkin/kin-openapi.
Check the vendor advisory for the affected versions of github.com/getkin/kin-openapi.
Severity: Medium (CVSS 5.3/10). Risk of unauthorized operations or information disclosure.
Update to 0.145.0.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'github.com/getkin/kin-openapi' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'github.com/getkin/kin-openapi' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
github.com/getkin/kin-openapiを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade github.com/getkin/kin-openapi to 0.145.0ステージング環境で 0.145.0 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2026-100348 golang-github-getkin-kin-openapi
- Ubuntu UBUNTU-CVE-2026-100348 golang-github-getkin-kin-openapi
References
- advisory nvd.nist.gov
- package github.com
- web github.com
- web github.com
- web github.com
- web github.com