CVE-2026-87803

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-87803
StatePUBLISHED
Assignersnyk
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-10 10:17:32 UTC
Updated2026-09-10 15:53:23 UTC
DescriptionAn authorization bypass vulnerability exists in the Countly Server DBViewer due to flawed sub-pipeline detection in the aggregation stage sanitizer. The /o/db aggregation endpoint parses user-controlled aggregation JSON and passes it through a stage sanitizer that determines whether a nested array is a sub-pipeline by checking if every element contains a key present in a hardcoded KNOWN_STAGE_OPERATORS set. If any element contains an unrecognized stage key, such as the undocumented MongoDB-internal $_internalInhibitOptimization, the sanitizer misclassifies the entire branch as a generic array and skips stage-level stripping for all sibling stages. This allows a non-admin user with DBViewer read permission to inject forbidden operators like $lookup inside $facet sub-pipelines, performing cross-collection joins into restricted collections. This leads to unauthorized read access to sensitive data including password-reset tokens (prid), enabling account takeover.

Risk And Classification

Primary CVSS: v4.0 7.1 HIGH from [email protected]

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS: 0.003080000 probability, percentile 0.233080000 (date 2026-09-10)

Problem Types: CWE-863 | CWE-863 Countly DBViewer authorization bypass via nested aggregation stage poisoning

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary7.1HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/C...
4.0CNADECLARED7.1HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N
3.1[email protected]Secondary7.1HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N
3.1CNADECLARED7.1HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
Low
User Interaction
None
Confidentiality
High
Integrity
Low
Availability
None
Sub Conf.
None
Sub Integrity
None
Sub Availability
None

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Countly Countly-server affected 25.03.53-LTS semver Not specified

References

ReferenceSourceLinkTags
github.com/Countly/countly-server/pull/7868 [email protected] github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Catalin Iovita (Snyk Security Research) (en)

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