CVE-2026-84969
Heap overflow via truncated base64 encoding of binary fields in length-limited JSON output
A memory-handling error in the BSON-to-JSON conversion helpers of the MongoDB C Driver can write a small number of bytes past the end of a heap buffer when a binary field is encoded and the output is cut short at a caller-configured length limit. A party who supplies the document content, with no privileges on the application that links the driver, may cause a small amount of data outside the intended buffer to be altered.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
6.3
Heap overflow via truncated base64 encoding of binary fields in length-limited JSON output
A memory-handling error in the BSON-to-JSON conversion helpers of the MongoDB C Driver can write a small number of bytes past the end of a heap buffer when a binary field is encoded and the output is cut short at a caller-configured length limit. A party who supplies the document content, with no privileges on the application that links the driver, may cause a small amount of data outside the intended buffer to be altered.
- Record
CVE-2026-84969- CVSS 4.0
- 6.3 Medium
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N - CVSS 3.1
- 3.7 Low
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N - Weakness
- CWE-787
- Updated
- 2026-11-02
EUVDEUVD-2026-70508
6.3
A memory-handling error in the BSON-to-JSON conversion helpers of the MongoDB C Driver can write a small number of bytes past the end of a heap buffer when a binary field is encoded and the output is cut short at a caller-configured length limit. A party who supplies the document content, with no privileges on the application that links the driver, may cause a small amount of data outside the intended buffer to be altered.
- Record
EUVD-2026-70508- CVSS 4.0
- 6.3 Medium
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-9xr7-hhfx-wh4c
6.3
A memory-handling error in the BSON-to-JSON conversion helpers of the MongoDB C Driver can write...
A memory-handling error in the BSON-to-JSON conversion helpers of the MongoDB C Driver can write a small number of bytes past the end of a heap buffer when a binary field is encoded and the output is cut short at a caller-configured length limit. A party who supplies the document content, with no privileges on the application that links the driver, may cause a small amount of data outside the intended buffer to be altered.
- Record
GHSA-9xr7-hhfx-wh4c- CVSS 4.0
- 6.3 Medium
CVSS:4.0/AV:N/AC:L/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 Low
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N - Weakness
- CWE-787
- Updated
- 2026-11-02
NVD
6.3
A memory-handling error in the BSON-to-JSON conversion helpers of the MongoDB C Driver can write a small number of bytes past the end of a heap buffer when a binary field is encoded and the output is cut short at a caller-configured length limit. A party who supplies the document content, with no privileges on the application that links the driver, may cause a small amount of data outside the intended buffer to be altered.
- Record
CVE-2026-84969- CVSS 4.0
- 6.3 Medium
CVSS:4.0/AV:N/AC:L/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 Low
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N - CVSS 3.1
- 3.7 Low
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N - Weakness
- CWE-787
- Updated
- 2026-11-02
OSVALPINE-CVE-2026-84969
3.7
A memory-handling error in the BSON-to-JSON conversion helpers of the MongoDB C Driver can write a small number of bytes past the end of a heap buffer when a binary field is encoded and the output is cut short at a caller-configured length limit. A party who supplies the document content, with no privileges on the application that links the driver, may cause a small amount of data outside the intended buffer to be altered.
- Record
ALPINE-CVE-2026-84969- CVSS 3.1
- 3.7 Low
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N - Updated
- 2026-11-03
OSV
6.3
Heap overflow via truncated base64 encoding of binary fields in length-limited JSON output
A memory-handling error in the BSON-to-JSON conversion helpers of the MongoDB C Driver can write a small number of bytes past the end of a heap buffer when a binary field is encoded and the output is cut short at a caller-configured length limit. A party who supplies the document content, with no privileges on the application that links the driver, may cause a small amount of data outside the intended buffer to be altered.
- Record
CVE-2026-84969- CVSS 4.0
- 6.3 Medium
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N - Weakness
- CWE-787
- Updated
- 2026-11-02
Show 7 moreShow less
OSVDEBIAN-CVE-2026-84969
3.7
A memory-handling error in the BSON-to-JSON conversion helpers of the MongoDB C Driver can write a small number of bytes past the end of a heap buffer when a binary field is encoded and the output is cut short at a caller-configured length limit. A party who supplies the document content, with no privileges on the application that links the driver, may cause a small amount of data outside the intended buffer to be altered.
- Record
DEBIAN-CVE-2026-84969- CVSS 3.1
- 3.7 Low
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N - Updated
- 2026-11-02
OSVOESA-2026-4352
6.3
mongo-c-driver security update
mongo-c-driver is a project that includes two libraries: libmongoc, a client library written in C for MongoDB. libbson, a library providing useful routines related to building, parsing, and iterating BSON documents.
Security Fix(es):
A weakness in the MongoDB C Driver allows special elements in caller-supplied database and collection name components to pass without sanitization when the driver composes the target namespace for an operation. An application that incorporates untrusted input into these name components can have operations directed at a resource other than the one intended.(CVE-2026-81524)
An incorrect numeric conversion in the JSON parsing component of the MongoDB C Driver's BSON library may cause an unusually large text value to be silently shortened, or the corresponding field to be omitted, while the parsing operation still reports success and returns no error. An unauthenticated party who can supply the input processed by an application that uses this component may cause that application to hold data that does not match what was submitted, which may result in unintended alteration of data.(CVE-2026-84963)
A double free in the OpenSSL-based TLS certificate revocation checking path of the MongoDB C Driver can be reached by a TLS endpoint that the client already trusts. During the handshake, specially formed certificate data can cause the same heap object to be released twice. An unauthenticated party acting as the trusted endpoint may cause the connecting client application to terminate unexpectedly.(CVE-2026-84964)
An integer wraparound in an allocation size calculation in the BSON library's JSON parsing code can cause a buffer to be released while a following copy operation still writes through the stale pointer. On builds where sizes are 32 bits, an unauthenticated party able to supply a sufficiently large JSON input to an application that links the library may cause that application to terminate unexpectedly, resulting in denial of service.(CVE-2026-84965)
A memory-handling error in the BSON-to-JSON conversion helpers of the MongoDB C Driver can write a small number of bytes past the end of a heap buffer when a binary field is encoded and the output is cut short at a caller-configured length limit. A party who supplies the document content, with no privileges on the application that links the driver, may cause a small amount of data outside the intended buffer to be altered.(CVE-2026-84969)
- Record
OESA-2026-4352- CVSS 4.0
- 6.3 Medium
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N - Updated
- 2026-11-02
OSVOESA-2026-4353
6.3
mongo-c-driver security update
mongo-c-driver is a project that includes two libraries: libmongoc, a client library written in C for MongoDB. libbson, a library providing useful routines related to building, parsing, and iterating BSON documents.
Security Fix(es):
A weakness in the MongoDB C Driver allows special elements in caller-supplied database and collection name components to pass without sanitization when the driver composes the target namespace for an operation. An application that incorporates untrusted input into these name components can have operations directed at a resource other than the one intended.(CVE-2026-81524)
An incorrect numeric conversion in the JSON parsing component of the MongoDB C Driver's BSON library may cause an unusually large text value to be silently shortened, or the corresponding field to be omitted, while the parsing operation still reports success and returns no error. An unauthenticated party who can supply the input processed by an application that uses this component may cause that application to hold data that does not match what was submitted, which may result in unintended alteration of data.(CVE-2026-84963)
A double free in the OpenSSL-based TLS certificate revocation checking path of the MongoDB C Driver can be reached by a TLS endpoint that the client already trusts. During the handshake, specially formed certificate data can cause the same heap object to be released twice. An unauthenticated party acting as the trusted endpoint may cause the connecting client application to terminate unexpectedly.(CVE-2026-84964)
An integer wraparound in an allocation size calculation in the BSON library's JSON parsing code can cause a buffer to be released while a following copy operation still writes through the stale pointer. On builds where sizes are 32 bits, an unauthenticated party able to supply a sufficiently large JSON input to an application that links the library may cause that application to terminate unexpectedly, resulting in denial of service.(CVE-2026-84965)
A memory-handling error in the BSON-to-JSON conversion helpers of the MongoDB C Driver can write a small number of bytes past the end of a heap buffer when a binary field is encoded and the output is cut short at a caller-configured length limit. A party who supplies the document content, with no privileges on the application that links the driver, may cause a small amount of data outside the intended buffer to be altered.(CVE-2026-84969)
- Record
OESA-2026-4353- CVSS 4.0
- 6.3 Medium
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N - Updated
- 2026-11-02
OSVOESA-2026-4354
6.3
mongo-c-driver security update
mongo-c-driver is a project that includes two libraries: libmongoc, a client library written in C for MongoDB. libbson, a library providing useful routines related to building, parsing, and iterating BSON documents.
Security Fix(es):
A weakness in the MongoDB C Driver allows special elements in caller-supplied database and collection name components to pass without sanitization when the driver composes the target namespace for an operation. An application that incorporates untrusted input into these name components can have operations directed at a resource other than the one intended.(CVE-2026-81524)
An incorrect numeric conversion in the JSON parsing component of the MongoDB C Driver's BSON library may cause an unusually large text value to be silently shortened, or the corresponding field to be omitted, while the parsing operation still reports success and returns no error. An unauthenticated party who can supply the input processed by an application that uses this component may cause that application to hold data that does not match what was submitted, which may result in unintended alteration of data.(CVE-2026-84963)
A double free in the OpenSSL-based TLS certificate revocation checking path of the MongoDB C Driver can be reached by a TLS endpoint that the client already trusts. During the handshake, specially formed certificate data can cause the same heap object to be released twice. An unauthenticated party acting as the trusted endpoint may cause the connecting client application to terminate unexpectedly.(CVE-2026-84964)
An integer wraparound in an allocation size calculation in the BSON library's JSON parsing code can cause a buffer to be released while a following copy operation still writes through the stale pointer. On builds where sizes are 32 bits, an unauthenticated party able to supply a sufficiently large JSON input to an application that links the library may cause that application to terminate unexpectedly, resulting in denial of service.(CVE-2026-84965)
A memory-handling error in the BSON-to-JSON conversion helpers of the MongoDB C Driver can write a small number of bytes past the end of a heap buffer when a binary field is encoded and the output is cut short at a caller-configured length limit. A party who supplies the document content, with no privileges on the application that links the driver, may cause a small amount of data outside the intended buffer to be altered.(CVE-2026-84969)
- Record
OESA-2026-4354- CVSS 4.0
- 6.3 Medium
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N - Updated
- 2026-11-02
OSVOESA-2026-4355
6.3
mongo-c-driver security update
mongo-c-driver is a project that includes two libraries: libmongoc, a client library written in C for MongoDB. libbson, a library providing useful routines related to building, parsing, and iterating BSON documents.
Security Fix(es):
A weakness in the MongoDB C Driver allows special elements in caller-supplied database and collection name components to pass without sanitization when the driver composes the target namespace for an operation. An application that incorporates untrusted input into these name components can have operations directed at a resource other than the one intended.(CVE-2026-81524)
An incorrect numeric conversion in the JSON parsing component of the MongoDB C Driver's BSON library may cause an unusually large text value to be silently shortened, or the corresponding field to be omitted, while the parsing operation still reports success and returns no error. An unauthenticated party who can supply the input processed by an application that uses this component may cause that application to hold data that does not match what was submitted, which may result in unintended alteration of data.(CVE-2026-84963)
A double free in the OpenSSL-based TLS certificate revocation checking path of the MongoDB C Driver can be reached by a TLS endpoint that the client already trusts. During the handshake, specially formed certificate data can cause the same heap object to be released twice. An unauthenticated party acting as the trusted endpoint may cause the connecting client application to terminate unexpectedly.(CVE-2026-84964)
An integer wraparound in an allocation size calculation in the BSON library's JSON parsing code can cause a buffer to be released while a following copy operation still writes through the stale pointer. On builds where sizes are 32 bits, an unauthenticated party able to supply a sufficiently large JSON input to an application that links the library may cause that application to terminate unexpectedly, resulting in denial of service.(CVE-2026-84965)
A memory-handling error in the BSON-to-JSON conversion helpers of the MongoDB C Driver can write a small number of bytes past the end of a heap buffer when a binary field is encoded and the output is cut short at a caller-configured length limit. A party who supplies the document content, with no privileges on the application that links the driver, may cause a small amount of data outside the intended buffer to be altered.(CVE-2026-84969)
- Record
OESA-2026-4355- CVSS 4.0
- 6.3 Medium
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N - Updated
- 2026-11-02
OSVUBUNTU-CVE-2026-84969
6.3
A memory-handling error in the BSON-to-JSON conversion helpers of the MongoDB C Driver can write a small number of bytes past the end of a heap buffer when a binary field is encoded and the output is cut short at a caller-configured length limit. A party who supplies the document content, with no privileges on the application that links the driver, may cause a small amount of data outside the intended buffer to be altered.
- Record
UBUNTU-CVE-2026-84969- CVSS 4.0
- 6.3 Medium
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N - CVSS 3.1
- 3.7 Low
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N - Updated
- 2026-11-02
OSVopenSUSE-SU-2026:11706-1 No score
bson-devel-2.5.2-1.1 on GA media
These are all security issues fixed in the bson-devel-2.5.2-1.1 package on the GA media of openSUSE Tumbleweed.
- Record
openSUSE-SU-2026:11706-1- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
mongo-c-driverAlpine:v3.24 |
before 1.30.14-r0 | 1.30.14-r0 |
mongo-c-driverDebian:13 |
All versions, plus listed versions 1.30.4-11.30.4-1+deb13u11.30.4-1+deb13u21.30.4-1+deb13u32.0.2-1 Show 18 moreShow less2.1.0-12.1.1-12.1.2-12.2.0-12.2.1-12.2.2-12.2.3-12.2.4-12.3.0-12.3.1-12.3.2-12.3.3-12.4.0-12.5.0-12.5.1-12.5.2-12.5.3-12.5.5-1 |
None known |
mongo-c-driverDebian:14 |
before 2.5.2-1, plus listed versions 1.30.4-12.0.2-12.1.0-12.1.1-12.1.2-1 Show 12 moreShow less2.2.0-12.2.1-12.2.2-12.2.3-12.2.4-12.3.0-12.3.1-12.3.2-12.3.3-12.4.0-12.5.0-12.5.1-1 |
2.5.2-1 |
mongo-c-driveropenEuler:22.03-LTS-SP4 From an advisory covering 5 CVEs |
before 1.30.9-1.oe2203sp4 | 1.30.9-1.oe2203sp4 |
mongo-c-driveropenEuler:24.03-LTS-SP1 From an advisory covering 5 CVEs |
before 1.30.9-1.oe2403sp1 | 1.30.9-1.oe2403sp1 |
mongo-c-driveropenEuler:24.03-LTS-SP3 From an advisory covering 5 CVEs |
before 1.30.9-1.oe2403sp3 | 1.30.9-1.oe2403sp3 |
mongo-c-driveropenEuler:24.03-LTS-SP4 From an advisory covering 5 CVEs |
before 1.30.9-1.oe2403sp4 | 1.30.9-1.oe2403sp4 |
mongo-c-driverUbuntu: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-driverUbuntu: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 less1.20.1-11.21.0-11.21.0-1build11.21.0-1ubuntu0.1~esm1 |
None known |
mongo-c-driverUbuntu: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 less1.26.0-11.26.0-1.1ubuntu11.26.0-1.1ubuntu21.26.0-1.1ubuntu2+esm1 |
None known |
mongo-c-driverUbuntu: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-driverUbuntu: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-driveropenSUSE:Tumbleweed From an advisory covering 4 CVEs |
before 2.5.2-1.1 | 2.5.2-1.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, facts | ||
| affected, aliases, references | OSV | |
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-84969 is a medium vulnerability (CVSS 6.3) in Mongodb C Driver, published September 3, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.27%, the 19th percentile. Fixed in mongo-c-driver 1.30.14-r0.
References
jira.mongodb.org/browse/CDRIVER-6410
nvd.nist.gov/vuln/detail/CVE-2026-84969
github.com/advisories/GHSA-9xr7-hhfx-wh4c
security.alpinelinux.org/vuln/CVE-2026-84969
github.com/CVEProject/cvelistV5/tree/main/cves/2026/84xxx/CVE-2026-84969.json
security-tracker.debian.org/tracker/CVE-2026-84969
Show 14 moreShow less
openeuler.org/zh/security/security-bulletins/detail?id=openEuler-SA-2026-4352
nvd.nist.gov/vuln/detail/CVE-2026-81524
nvd.nist.gov/vuln/detail/CVE-2026-84963
nvd.nist.gov/vuln/detail/CVE-2026-84964
nvd.nist.gov/vuln/detail/CVE-2026-84965
openeuler.org/zh/security/security-bulletins/detail?id=openEuler-SA-2026-4353
openeuler.org/zh/security/security-bulletins/detail?id=openEuler-SA-2026-4354
openeuler.org/zh/security/security-bulletins/detail?id=openEuler-SA-2026-4355
ubuntu.com/security/CVE-2026-84969
cve.org/CVERecord?id=CVE-2026-84969
suse.com/security/cve/CVE-2026-84963
suse.com/security/cve/CVE-2026-84964
suse.com/security/cve/CVE-2026-84965
suse.com/security/cve/CVE-2026-84969