CVE-2026-96749: Heap out-of-bounds write via signed size overflow in BSON document encoding
Noroxi assessment
Priority: Monitor (action score 30/100)
- 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: 0.18% (FIRST EPSS).
- Someone with local access to the system can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
- Fixed version: MongoDB Python Driver 4.18.2.
Low priority for now. Upgrade to MongoDB Python Driver 4.18.2 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 overflow in the BSON document encoding component of the MongoDB Python Driver's bundled native extension may occur when a single document is built from an unusually large amount of caller-supplied data. Size arithmetic is performed in a signed 32-bit type, and the guard meant to catch the overflow is written in a form whose behavior is not defined by the C language standard. A party with no privileges who can place a very large value into data that an application encodes may, depending on how the native extension was built, cause a write outside the bounds of an allocated buffer inside the application's own process.
- Published
- Sep 24, 2026
- Updated
- Sep 26, 2026
- EPSS
- 0.1% · 8th percentile
- CWE
- CWE-190
Report tools
Action score
30
Monitor
Low priority for now.
- CVSS
- 30 / 40 · 7.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.1%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- total
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · mongodb
- 7.5
- NVD has not scored this yet; the score shown is the CNA’s.
CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/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.
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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.
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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 Python Driver
- 1.9.0 and later · before 4.18.2affected · semver
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | pymongo | from 0 | — |
| Debian:14 | pymongo | before 4.18.2-1 | 4.18.2-1 |
| openSUSE:Leap 16.0 | python-pymongo | before 4.6.3-bp160.2.1 | 4.6.3-bp160.2.1 |
| openSUSE:Tumbleweed | python-pymongo | before 4.18.2-1.1 | 4.18.2-1.1 |
| PyPI | pymongo | before 4.18.2 | 4.18.2 |
| SUSE:Linux Enterprise Module for Package Hub 15 SP7 | python-pymongo | before 3.11.0-150300.3.6.1 | 3.11.0-150300.3.6.1 |
Same product
mongodb: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-96748Connection redirection via percent-encoded delimiter injection in connection string hosts33Monitor
- CVE-2026-88029GridFS data disclosure and deletion via query-operator injection in file IDs in the MongoDB Python Driver24Monitor
- CVE-2026-106435Application denial of service via out-of-bounds read in BSON Regex decoding in MongoDB Python Driver23Monitor
Published before and after this one in the same product
- ← EarlierCVE-2026-96747Sep 24, 2026 · Forced local Unix socket connection via dot-sock KMS endpoint in client-side field encryption21Monitor
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 Python Driver | 4.18.2 | Vendor (CNA) |
| debian:pymongo | 4.18.2-1 · Debian:14 | Package registry (OSV) |
| opensuse:python-pymongo | 4.18.2-1.1 · openSUSE:Tumbleweed | Package registry (OSV) |
| PyPI:pymongo | 4.18.2 | Package registry (OSV) |
| suse:python-pymongo | 3.11.0-150300.3.6.1 · SUSE:Linux Enterprise Module for Package Hub 15 SP7 | 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.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
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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.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- Integrity
- Availability
- Attack vector
- Local
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- X
Weakness class (CWE)
CWE-190 · Integer Overflow or WraparoundCVSS vector
CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/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
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Change log
- Fix✗ → ✓
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References
Show all references (2 more)Show less
Vendor advisories and official records. Exploit/PoC links are deliberately left out.