Heap overflow via oversized RSA signature in GCP KMS signing callback

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-126792
StatePUBLISHED
Assignermongodb
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-11-13 00:20:12 UTC
Updated2026-11-13 00:20:12 UTC
DescriptionA memory-safety flaw in the key-management request-building component of the library can lead to an out-of-bounds write on the heap. A fixed-size output buffer is used under an assumption about cryptographic key size that is never validated, so when the library is embedded by a caller that supplies its own cryptographic callback implementation, data larger than the buffer can be written past its end. Exploitation requires the ability to control the embedding application's in-process key-management provider configuration, a high-privilege position. The demonstrated impact is memory corruption resulting in abnormal termination of the client process.

Risk And Classification

Primary CVSS: v4.0 5.7 MEDIUM from [email protected]

CVSS:4.0/AV:L/AC:H/AT:P/PR:H/UI:N/VC:N/VI:L/VA:H/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

Problem Types: CWE-787 | CWE-787 CWE-787: Out-of-bounds Write

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary5.7MEDIUMCVSS:4.0/AV:L/AC:H/AT:P/PR:H/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N/E:X/C...
4.0CNACVSS5.6MEDIUMCVSS:4.0/AV:L/AC:H/AT:P/PR:H/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N
3.1[email protected]Secondary4.7MEDIUMCVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:L/A:H
3.1CNACVSS4.7MEDIUMCVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:L/A:H

CVSS v4.0 Breakdown

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

CVSS:4.0/AV:L/AC:H/AT:P/PR:H/UI:N/VC:N/VI:L/VA:H/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
Local
Attack Complexity
High
Privileges Required
High
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
High

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA MongoDB Libmongocrypt Driver affected 1.1.0 1.21.2 python Not specified

References

ReferenceSourceLinkTags
jira.mongodb.org/browse/MONGOCRYPT-975 [email protected] jira.mongodb.org
jira.mongodb.org/browse/PYTHON-5999 [email protected] jira.mongodb.org
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