Fix query parameter truncation with configurable limit (fixes #5878)#7117
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nmurrell07 wants to merge 1 commit intoexpressjs:masterfrom
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Fix query parameter truncation with configurable limit (fixes #5878)#7117nmurrell07 wants to merge 1 commit intoexpressjs:masterfrom
nmurrell07 wants to merge 1 commit intoexpressjs:masterfrom
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- Change default query parser from 'simple' to 'extended' - Add 'query parser limit' setting with default of 10000 - Pass limit to query parser at parse time (not compile time) - Fixes issue expressjs#5878 - query params truncated at 1000+ params - Supersedes PR expressjs#7116 which used Infinity (security concern)
krzysdz
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Mar 21, 2026
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Some other notes:
- My understanding of #5878 is that quietly dropping params is unexpected, not necessarily a specific limit value.
- In my opinion an Express-level query parsing configuration limit should apply to all non-custom (that is
'simple'and'extended') parsers.
| this.set('etag', 'weak'); | ||
| this.set('env', env); | ||
| this.set('query parser', 'simple') | ||
| this.set('query parser', 'extended') |
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'query parser' changed to 'simple' in Express 5 (#3621) and I don't think reverting to 'extended' is planned.
| this.set('env', env); | ||
| this.set('query parser', 'simple') | ||
| this.set('query parser', 'extended') | ||
| this.set('query parser limit', 10000) |
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In my opinion any new limit setting should be the same as current one (1000 in this case).
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Summary
This PR fixes issue #5878 where query parameters are silently truncated at 1000+ params due to the
qslibrary's defaultparameterLimitof 1000.Instead of setting
parameterLimit: Infinity(which was the approach in PR #7116 and could enable DoS via massive query strings), this PR:query parser limitsetting (default: 10000)app.set('query parser limit', N)qs.parse()at parse timeChanges
lib/utils.js—parseExtendedQueryStringaccepts a limit parameterlib/request.js— readsquery parser limitfrom app settingslib/application.js— sets defaultquery parser limitto 10000Supersedes
parameterLimit: Infinity)I'm fairly new to contributing to express — would appreciate any feedback on the approach! Happy to iterate.
Fixes #5878