CVE-2026-84965: Heap write primitive via size round-up wrap during JSON parsing on 32-bit builds
Noroxi assessment
Priority: Monitor (action score 23/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 0.12% (FIRST EPSS).
- Someone with local access to the system can trigger it. No account or password is required. No user action is required. Special conditions such as timing or configuration are required.
- Fixed version: MongoDB C Driver 1.30.9, 2.5.2.
Low priority for now. Upgrade to MongoDB C Driver 1.30.9, 2.5.2 or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
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.
- Published
- Sep 3, 2026
- Updated
- Sep 22, 2026
- EPSS
- 0.1% · 2th percentile
- CWE
- CWE-190
Report tools
Action score
23
Monitor
Low priority for now.
- CVSS
- 23 / 40 · 5.9 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.1%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · mongodb
- 5.9
- NVD has not scored this yet; the score shown is the CNA’s.
CVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
Running WordPress? Scan your site free with WP Lens
Noroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| Vendor | Product | CPE |
|---|---|---|
| mongodb | c driver | cpe:2.3:a:mongodb:c_driver |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- mongodb c driver1.10.0 and later · before 1.30.9
- mongodb c driver2.0.0 and later · before 2.5.2
Versions reported by the vendor
Affected version ranges reported by the assigning authority (mongodb). Independent of NVD's CPE analysis and usually ahead of it.
MongoDB C Driver
- 1.10.0 and later · before 1.30.9affected · semver
- 2.0.0 and later · before 2.5.2affected · semver
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Alpine:v3.24 | mongo-c-driver | before 1.30.14-r0 | 1.30.14-r0 |
| Debian:12 | mongo-c-driver | from 0 | — |
| Debian:14 | mongo-c-driver | before 2.5.2-1 | 2.5.2-1 |
| openSUSE:Tumbleweed | mongo-c-driver | before 2.5.2-1.1 | 2.5.2-1.1 |
Same product
mongodb: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-93393Heap overflow via oversized decrypted TLS record sequence in Windows Secure Channel stream36Monitor
- CVE-2026-120955MongoDB C Driver Modern GridFS mongoc_gridfs_bucket_download_to_stream() Aborts Application on Malformed GridFS Metadata34Monitor
- CVE-2026-120678MongoDB C Driver leaks the decompressed reply buffer when an OP_COMPRESSED reply fails to parse (denial of service)34Monitor
Published before and after this one in the same product
- ← EarlierCVE-2026-84963Sep 3, 2026 · Silent field truncation via unchecked int cast of huge JSON string values in JSON-to-BSON parser25Monitor
- ← EarlierCVE-2026-84964Sep 3, 2026 · Heap corruption via OCSP request double free from crafted multi-URL certificate in TLS client32Monitor
- Later →CVE-2026-88035Sep 10, 2026 · Heap buffer overflow via wrapped size check during SASL username canonicalization in MongoDB C Driver22Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| MongoDB C Driver | 1.30.9 | Vendor (CNA) |
| MongoDB C Driver | 2.5.2 | Vendor (CNA) |
| alpine:mongo-c-driver | 1.30.14-r0 · Alpine:v3.24 | Package registry (OSV) |
| debian:mongo-c-driver | 2.5.2-1 · Debian:14 | Package registry (OSV) |
| opensuse:mongo-c-driver | 2.5.2-1.1 · openSUSE:Tumbleweed | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
- CVE-2026-12095461 days apartSilent element-count truncation via 32-bit bit-length overflow in packed-bit vector views25Monitor
- CVE-2026-880357 days apartHeap buffer overflow via wrapped size check during SASL username canonicalization in MongoDB C Driver22Monitor
- CVE-2026-11464549 days apartHeap overflow via 32-bit length wrap of the URI username in Windows Kerberos auth message wrapping22Monitor
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.
Technical details
Attack conditions
- Someone with local access to the system can trigger it.
- No account or password is required.
- No user action is required.
- Special conditions such as timing or configuration are required.
If successful
- Confidentiality
- Integrity
- Availability
- Attack vector
- Local
- Attack complexity
- High
- Privileges required
- None
- User interaction
- None
- Scope
- X
Weakness class (CWE)
CWE-190 · Integer Overflow or WraparoundCVSS vector
CVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/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
nvd-secondary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
ATT&CK techniques
—
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Vendor advisories and official records. Exploit/PoC links are deliberately left out.