fix(commons): skip prototype-polluting keys in _.merge - #3695
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Object.keys() returns __proto__ as an own enumerable key for JSON-parsed sources, causing the recursive merge to write onto Object.prototype. Skip __proto__/constructor/prototype keys. Same remediation as dove #3690 / @feathersjs/commons@5.0.45 (GHSA-28xv-ph75-77wh / CVE-2026-54335). Reported-by: Andrew Ridings (@ridingsa)
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Summary
Backport of the Dove fix for GHSA-28xv-ph75-77wh / CVE-2026-54335 to Crow (Feathers 4.x).
The recursive
_.mergehelper in@feathersjs/commonsiteratesObject.keys(source). When the source came fromJSON.parse('{"__proto__":...}'),__proto__is returned as an own-enumerable key, so the recursive call resolvestarget['__proto__']toObject.prototypeand writes onto it.This adds the standard guard to skip
__proto__,constructor, andprototypekeys during iteration — the same remediation as dove #3690 /@feathersjs/commons@5.0.45.Related: #3690 (dove), #3687 (original report by @ridingsa), GHSA-28xv-ph75-77wh.
No dependency on other repos.
Changes
packages/commons/src/utils.ts: skip the three prototype-mutating keys in the merge loop.packages/commons/test/utils.test.ts: regression test confirming a JSON-parsed__proto__/constructor.prototypesource no longer mutatesObject.prototype.Notes
mergestill works for all documented input shapes.@feathersjs/commons@4.5.20(and bump dependents as needed for the Crow release), then update GHSA-28xv-ph75-77wh with a Crow patched range (<= 4.5.19→4.5.20).Reported-by: Andrew Ridings (@ridingsa)
Verification