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CVE-2026-120954

Silent element-count truncation via 32-bit bit-length overflow in packed-bit vector views

6.3 Medium

A weakness in the BSON library's handling of a specialized binary vector data type allows an arithmetic wraparound when computing the number of elements described by an oversized attacker-supplied value. On builds where the platform word size is 32 bits, an application that parses untrusted BSON data can be made to process only a small fraction of the supplied elements while the operation reports success, producing results that disagree with byte-oriented accessors and with 64-bit builds of the same library. No authentication or user interaction is required beyond getting the application to parse the data. The impact is limited to data integrity; memory safety is not affected and no information is disclosed.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
High
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
None
Integrity
Low
Availability
None

Exploit likelihood

0.23%Unchanged since Nov 4, 2026
90%50%10%1%

What each source reports

CVE List Score used 6.3

Silent element-count truncation via 32-bit bit-length overflow in packed-bit vector views

A weakness in the BSON library's handling of a specialized binary vector data type allows an arithmetic wraparound when computing the number of elements described by an oversized attacker-supplied value. On builds where the platform word size is 32 bits, an application that parses untrusted BSON data can be made to process only a small fraction of the supplied elements while the operation reports success, producing results that disagree with byte-oriented accessors and with 64-bit builds of the same library. No authentication or user interaction is required beyond getting the application to parse the data. The impact is limited to data integrity; memory safety is not affected and no information is disclosed.

Record
CVE-2026-120954
CVSS 4.0
6.3 MediumCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
CVSS 3.1
3.7 LowCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
Weakness
CWE-190
Updated
2026-11-03
EUVDEUVD-2026-116140 6.3

A weakness in the BSON library's handling of a specialized binary vector data type allows an arithmetic wraparound when computing the number of elements described by an oversized attacker-supplied value. On builds where the platform word size is 32 bits, an application that parses untrusted BSON data can be made to process only a small fraction of the supplied elements while the operation reports success, producing results that disagree with byte-oriented accessors and with 64-bit builds of the same library. No authentication or user interaction is required beyond getting the application to parse the data. The impact is limited to data integrity; memory safety is not affected and no information is disclosed.

Record
EUVD-2026-116140
CVSS 4.0
6.3 MediumCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
Updated
2026-11-03
NVD 6.3

A weakness in the BSON library's handling of a specialized binary vector data type allows an arithmetic wraparound when computing the number of elements described by an oversized attacker-supplied value. On builds where the platform word size is 32 bits, an application that parses untrusted BSON data can be made to process only a small fraction of the supplied elements while the operation reports success, producing results that disagree with byte-oriented accessors and with 64-bit builds of the same library. No authentication or user interaction is required beyond getting the application to parse the data. The impact is limited to data integrity; memory safety is not affected and no information is disclosed.

Record
CVE-2026-120954
CVSS 4.0
6.3 MediumCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/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 3.1
3.7 LowCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
Weakness
CWE-190
Updated
2026-11-03
OSVUBUNTU-CVE-2026-120954 6.3

A weakness in the BSON library's handling of a specialized binary vector data type allows an arithmetic wraparound when computing the number of elements described by an oversized attacker-supplied value. On builds where the platform word size is 32 bits, an application that parses untrusted BSON data can be made to process only a small fraction of the supplied elements while the operation reports success, producing results that disagree with byte-oriented accessors and with 64-bit builds of the same library. No authentication or user interaction is required beyond getting the application to parse the data. The impact is limited to data integrity; memory safety is not affected and no information is disclosed.

Record
UBUNTU-CVE-2026-120954
CVSS 4.0
6.3 MediumCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
CVSS 3.1
3.7 LowCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
Updated
2026-11-05
OSVopenSUSE-SU-2026:12437-1 No score

bson-devel-2.5.8-1.1 on GA media

These are all security issues fixed in the bson-devel-2.5.8-1.1 package on the GA media of openSUSE Tumbleweed.

Record
openSUSE-SU-2026:12437-1
Updated
2026-11-06

Affected products

Affected packages

Affected packages
PackageAffectedFixed
mongo-c-driver
Ubuntu:Pro:20.04:LTS
All versions, plus listed versions
1.15.0-11.15.1-11.15.2-11.16.0-11.16.1-11.16.1-1build11.16.1-1build21.16.1-1ubuntu0.1~esm1
None known
mongo-c-driver
Ubuntu:Pro:22.04:LTS
All versions, plus listed versions
1.18.0-11.19.1-11.19.2-11.20.0-11.20.0-1build1
Show 4 moreShow less
1.20.1-11.21.0-11.21.0-1build11.21.0-1ubuntu0.1~esm1
None known
mongo-c-driver
Ubuntu:Pro:24.04:LTS
All versions, plus listed versions
1.24.3-11.24.4-11.25.1-11.25.2-11.25.4-1
Show 4 moreShow less
1.26.0-11.26.0-1.1ubuntu11.26.0-1.1ubuntu21.26.0-1.1ubuntu2+esm1
None known
mongo-c-driver
Ubuntu:26.10
All versions, plus listed versions
2.2.2-12.3.1-12.3.2-12.3.3-1build12.5.0-1
None known
mongo-c-driver
Ubuntu:26.04:LTS
All versions, plus listed versions
1.30.4-1ubuntu12.2.0-12.2.1-12.2.2-1
None known
mongo-c-driver
openSUSE:Tumbleweed
From an advisory covering 5 CVEs
before 2.5.8-1.1
2.5.8-1.1

History

History
RecordedChangedSources
affected, aliases, referencesOSV
affected, aliases, referencesCVE List, EUVD, NVD, OSV
aliases, products, publishedEUVD
first indexedCVE List

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-120954 is a medium vulnerability (CVSS 6.3) in Mongodb C Driver, published November 3, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.23%, the 14th percentile. No source names a fixed version.

References

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