Axios v1.16.1

v1.16.1 — May 13, 2026

This release ships a defence-in-depth fix for prototype pollution in formDataToJSON, hardens proxy and CI workflows, restores Webpack 4 compatibility for the fetch adapter, and includes several small bug fixes and maintenance improvements.

🔒 Security Fixes

• Prototype Pollution Defence-in-Depth: Hardened formDataToJSON against already-polluted Object.prototype by walking own properties only, so attacker-controlled keys inherited from a poisoned prototype cannot propagate through deserialization. (#7413)
• Proxy Cleartext Leak: Fixed an issue where HTTPS request data could be transmitted in cleartext to an HTTP proxy under certain configurations. (#10858)
• CI Cache Removal: Removed all GitHub Actions caches as a defence-in-depth measure against cache poisoning vectors in the build pipeline. (#10882)

🐛 Bug Fixes

• Data URI Parsing: Updated the fromDataURI regex to match RFC 2397 more strictly, fixing edge cases in data: URL handling. (#10829)
• Unicode Headers: Preserved Unicode header values when running through request interceptors, so non-ASCII header content is no longer corrupted before dispatch. (#10850)
• XHR Upload Progress: Guarded against malformed ProgressEvent payloads emitted by some environments during XHR upload, preventing crashes when loaded / total are missing or invalid. (#10868)
• Webpack 4 Fetch Adapter: Fixed an "unexpected token" error caused by syntax in the fetch adapter that Webpack 4 could not parse, restoring compatibility for legacy bundler users. (#10864)
• Type Definitions: Made parseReviver context.source optional in the type definitions to align with the ES2023 specification. (#10837)
• URL Object Support Reverted: Reverted the change that allowed passing a URL object as config.url (originally #10866) due to regressions; this support will be reintroduced in a later release once the underlying issues are addressed. (#10874)

🔧 Maintenance & Chores

• Cycle Detection Refactor: Replaced the array-based cycle tracker in toJSONObject with a WeakSet, improving performance and memory behaviour on large nested structures. (#10832)
• composeSignals Cleanup: Refactored composeSignals to use a clearer early-return structure, simplifying the cancellation/abort composition path. (#10844)
• AI Readiness & Repo Docs: Added AGENTS.md and related contributor-guide updates for both human and AI agents, plus post-release documentation improvements. (#10835, #10841)
• Docs Improvements: Clarified the GET request example, fixed the interceptor eject example to reference the correct instance, and corrected the Buzzoid sponsor description in the README. (#10836, #10853, #10856)
• Sponsorship Tooling: Fixed empty sponsor arrays in the sponsor processing script, added the ability to inject additional sponsors, updated the sponsorship link, and added a Twicsy advertisement entry. (#10843, #10859, #10869)
• Dependencies: Bumped @commitlint/cli from 20.5.0 to 20.5.2. (#10846)

🌟 New Contributors

We are thrilled to welcome our new contributors. Thank you for helping improve axios:

• @hpinmetaverse (#10836)
• @tommyhgunz14 (#7413)
• @abhu85 (#10829)
• @divyanshuraj1095 (#10853)
• @sagodi97 (#10856)
• @rkdfx (#10868)
• @Liuwei1125 (#10866)

Full Changelog