axios 0.31.1

v0.31.1

on Node.js Yarn

This release backports a broad set of security hardenings from the v1 line — covering prototype-pollution defences, stream size enforcement, XSRF handling, URL null-byte encoding, and bounded FormData recursion — and drops committed dist/ artefacts along with Bower support.

⚠️ Breaking Changes & Deprecations

• Bower & Committed dist/ Removed: dist/ bundles are no longer committed to the repo, and bower.json plus the Grunt package2bower task have been removed. CI still builds bundles before publish, so npm/yarn/pnpm consumers are unaffected; installs via Bower or directly from the git tree must migrate to npm or a CDN. (#10747)

🔒 Security Fixes

• Prototype Pollution in Header Merge (GHSA-6chq-wfr3-2hj9): Tightened isFormData to reject plain/null-prototype objects and require append, and guarded the Node HTTP adapter so data.getHeaders() is only merged when it is not inherited from Object.prototype. Blocks injected headers via polluted getHeaders. (#10750)
• Prototype Pollution in Config Merging (GHSA-pf86-5x62-jrwf): mergeConfig, defaults resolution, and the HTTP adapter now uses own-property checks for transport, env, Blob, formSerializer, and transforms arrays, and merged configs are returned as null-prototype objects. Prevents hijacking of the request flow through polluted prototypes. (#10752)
• FormData / Params Recursion DoS: Added a configurable maxDepth (default 100, Infinity disables) to toFormData and params serialisation, throwing AxiosError with code ERR_FORM_DATA_DEPTH_EXCEEDED when exceeded. Circular-reference detection is preserved. (#10728)
• Null-Byte Injection in Query Strings: Removed the unsafe %00 → null-byte substitution from AxiosURLSearchParams.encode so %00 is preserved as-is. Other encoding behaviour (including %20 → +) unchanged. (#10737)
• Consolidated v1 Security Backport: Rolls up remaining v1 hardenings into v0.x: maxContentLength enforcement for responseType: 'stream' via a guarded transform with deferred piping, maxBodyLength enforcement for streamed uploads on native http/https with maxRedirects: 0, and stricter withXSRFToken handling so only own boolean true enables cross-origin XSRF headers. (#10764)

🔧 Maintenance & Chores

• CODEOWNERS: Added .github/CODEOWNERS with * @jasonsaayman to set a default reviewer for all paths. (#10740)

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