qs vulnerable to Prototype Pollution

Description

qs before 6.10.3 allows attackers to cause a Node process hang because an __ proto__ key can be used. In many typical web framework use cases, an unauthenticated remote attacker can place the attack payload in the query string of the URL that is used to visit the application, such as a[__proto__]=b&a[__proto__]&a[length]=100000000. The fix was backported to qs 6.9.7, 6.8.3, 6.7.3, 6.6.1, 6.5.3, 6.4.1, 6.3.3, and 6.2.4.

Basic information

Type
reviewed
Severity
high
Advisory on GitHub
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Repository advisory
Source code
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Published (advisory)
2022-11-27 00:30:50 UTC
Updated
2025-04-29 15:41:45 UTC
GitHub reviewed
2022-12-06 14:32:46 UTC
NVD published
2022-11-26 22:15:00 UTC

EPSS Score

Score Percentile
1.54% 81.38%

CVSS Scores

Base score Version Severity Vector
7.5 3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.

Identifiers

CWEs

CWE id Name
CWE-1321 Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')

Credits

  • dougwilson (analyst)

Affected packages (9)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem Package Vulnerable range First patched Vulnerable functions
npm qs >= 6.10.0, < 6.10.3 6.10.3
npm qs >= 6.9.0, < 6.9.7 6.9.7
npm qs >= 6.8.0, < 6.8.3 6.8.3
npm qs >= 6.7.0, < 6.7.3 6.7.3
npm qs >= 6.6.0, < 6.6.1 6.6.1
npm qs >= 6.5.0, < 6.5.3 6.5.3
npm qs >= 6.4.0, < 6.4.1 6.4.1
npm qs >= 6.3.0, < 6.3.3 6.3.3
npm qs < 6.2.4 6.2.4

References

cvelogic Threat Intelligence