Code Injection Duo — 2 CVEs, Peak CVSS 9.8 in openapi-typescript-codegen and Floci Velocity ThreatAft — Cybersecurity Intelligence / 11h Impact: CVE-108551 allows JavaScript injection into generated TypeScript clients via unescaped Handlebars interpolation — supply-chain compromise of build pipelines. If your CI/CD pipeline ingests OpenAPI specs from vendors, partners, or public repos, an attacker controlling that spec achieves code execution inside your build environment.

Two code injection vulnerabilities rated CVSS 9.8 were disclosed on October 10, 2026. One targets a widely used TypeScript code generator, poisoning build pipelines through untrusted OpenAPI documents. The other exploits an unauthenticated Velocity template engine in an AWS API Gateway emulator, achieving OS command execution inside the JVM. Both are CWE-94. Neither has a public exploit.

📌 TL;DR — Code Injection Duo

What: Two CVEs, both CVSS 3.1 9.8 / CVSS 4.0 9.3. CVE-2026-108551 — openapi-typescript-codegen through 0.31.0. CVE-2026-108598 — Floci 1.1.0 before 2.2.0. Impact: CVE-108551 allows JavaScript injection into generated TypeScript clients via unescaped Handlebars interpolation — supply-chain compromise of build pipelines. CVE-108598 allows unauthenticated OS command execution in the Floci JVM via Velocity template reflection. Exploit status: No public exploits. Not in CISA KEV. No known active exploitation. Fix: Floci 2.2.0. openapi-typescript-codegen fix pending beyond 0.31.0.

Supply-Chain Attack Surface: CVE-2026-108551 poisons generated TypeScript clients at build time. If your CI/CD pipeline ingests OpenAPI specs from vendors, partners, or public repos, an attacker controlling that spec achieves code execution inside your build environment.

Unauthenticated RCE in a Cloud Emulator: CVE-2026-108598 requires no credentials. Any user with API access to a vulnerable Floci instance can create a REST API with a MOCK integration and inject a malicious Velocity template.

Two Independent Injection Primitives: One exploits Handlebars template interpolation in a code generator. The other exploits Velocity template reflection in a runtime service. Different mechanisms, same CWE-94 outcome.

Downstream Blast Radius: CVE-2026-108551 compromises every consumer of the generated client — browser apps, Node services, and other build steps. CVE-2026-108598 compromises the host running the Floci service.

Patch Status Divergence: Floci has a confirmed fix in 2.2.0. openapi-typescript-codegen has no confirmed patched release yet.

CVE-2026-108551 — openapi-typescript-codegen Handlebars Injection (CVSS 9.8)

CVE-2026-108551 is classified as Improper Control of Generation of Code (CWE-94) . The flaw resides in the Handlebars templates used by openapi-typescript-codegen through version 0.31.0. The package is an npm library that generates TypeScript clients from OpenAPI specifications.

Root cause: The code generator interpolates user-controlled values into single-quoted JavaScript string literals without escaping. When an OpenAPI document contains a single quote in a path key, parameter name, servers[0].url , or info.version , the quote breaks out of the string literal and allows arbitrary JavaScript injection.

Attacker controls or influences an OpenAPI document processed by a build pipeline running openapi-typescript-codegen.

Attacker embeds a single quote and JavaScript payload in a path key, parameter name, servers[0].url , or info.version .

The code generator produces a TypeScript client containing the injected payload.

When the client is imported or a service method is called, the injected JavaScript executes in the consumer's context.

Impact: Supply-chain compromise. If your pipeline pulls OpenAPI specs from vendors, partners, internal service registries, or public repos, an attacker controlling that spec achieves code execution inside your build environment. That means secrets theft, CI/CD compromise, and downstream poisoning of every consumer of the generated client. Browser-side execution exposes end users to XSS-equivalent attacks.

Affected versions: openapi-typescript-codegen 0 through 0.31.0. No confirmed patched version at publication.

CVE-2026-108598 — Floci Velocity SSTI RCE (CVSS 9.8)

CVE-2026-108598 is classified as Improper Control of Generation of Code (CWE-94) , with VulDB additionally tagging it under CWE-78 (OS Command Injection), CWE-77, and CWE-74. The flaw resides in the VtlTemplateEngine component of Floci, an AWS API Gateway emulator.

Root cause: Floci 1.1.0 before 2.2.0 allows unrestricted Velocity mapping templates. An unauthenticated attacker can create a REST API with a MOCK integration whose template uses $util reflection to reach Runtime or ProcessBuilder .

Attacker sends an unauthenticated request to create a REST API with a MOCK integration.

The integration template uses $util reflection to access Java's Runtime or ProcessBuilder .

Arbitrary OS commands execute within the Floci JVM.

Impact: Full OS command execution on the host running the Floci service. If the Floci instance is exposed, this leads to complete system compromise.

Affected versions: Floci 1.1.0 before 2.2.0. Fixed in 2.2.0.

Affected Versions and Fixes

Upgrade Floci to 2.2.0. This is the confirmed fix for CVE-2026-108598 .

Upgrade Floci to 2.2.0. This is the confirmed fix for CVE-2026-108598 .

Inventory openapi-typescript-codegen usage. codebases and CI configs for the package. Pin or upgrade beyond 0.31.0 if a patched version becomes available, or migrate to a maintained fork.

Inventory openapi-typescript-codegen usage. codebases and CI configs for the package. Pin or upgrade beyond 0.31.0 if a patched version becomes available, or migrate to a maintained fork.

Sanitize OpenAPI specs. Treat all OpenAPI documents as untrusted input. Validate and reject specs containing quotes or suspicious characters in path keys, parameter names, servers[0].url , and info.version .

Sanitize OpenAPI specs. Treat all OpenAPI documents as untrusted input. Validate and reject specs containing quotes or suspicious characters in path keys, parameter names, servers[0].url , and info.version .

Regenerate and diff. Rebuild affected clients from clean specs and diff output against current artifacts to detect existing injections.

Regenerate and diff. Rebuild affected clients from clean specs and diff output against current artifacts to detect existing injections.

Rotate secrets if exposure is suspected. If any build ran against an untrusted spec recently, rotate tokens, signing keys, and registry credentials exposed to that pipeline.

Rotate secrets if exposure is suspected. If any build ran against an untrusted spec recently, rotate tokens, signing keys, and registry credentials exposed to that pipeline.

Compensating Controls (if patching is delayed)

ThreatAft defensive guidance, not official vendor advice.

Gate the pipeline: Add spec provenance checks and signed-spec verification before codegen runs in CI.

Restrict Floci API access: If upgrade is delayed, restrict the creation of REST APIs that use MOCK integrations and disallow $util reflection in Velocity templates.

Monitor API Gateway logs: Alert on attempts to insert or modify VTL mapping templates containing reflection calls.

CVE.org — CVE-2026-108551 (openapi-typescript-codegen)

CVE.org — CVE-2026-108598 (Floci)

CIRCL — Vulnerability Database

VulDB — Vulnerability Database

Two code injection flaws, both rated CVSS 9.8, demand different responses. Floci has a confirmed fix in 2.2.0 — upgrade immediately. openapi-typescript-codegen has no confirmed patch, so the priority is defense: inventory usage, sanitize every OpenAPI spec your pipeline processes, and treat all specs as untrusted input.

The openapi-typescript-codegen flaw is a supply-chain vector. The attacker does not need network access to your systems — they only need to influence a spec your build pipeline consumes. That makes provenance verification and spec signing the durable controls. The Floci flaw is a runtime vector — an unauthenticated attacker with API access achieves OS command execution. Both warrant immediate attention.

Upgrade Floci to 2.2.0. Inventory openapi-typescript-codegen usage. Sanitize all OpenAPI specs. Regenerate clients from clean specs and diff. Gate the pipeline with signed-spec verification.

— The ThreatAft Security Team

ThreatAft is an independent security publication. This analysis is based on research published by VulnCheck, CVE.org, CIRCL, and VulDB as of October 2026. Vulnerability information is time-sensitive; always refer to official sources for the most current guidance.