C Driver: Improper Validation of Specified Index, Position, or Offset in Input
CVE-2026-9100 is a high-severity improper validation of specified index, position, or offset in input vulnerability in C Driver from MongoDB, with a CVSS 3.1 base score of 7.1 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. The record lists versions 1.30.8, 2.2.4 as the first without the flaw, so updating C Driver to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.3% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update C Driver to 1.30.8 or 2.2.4, whichever matches your release line, or a later version.
- Read the advisory on jira.mongodb.org for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| MongoDB | C Driver | 1.0 up to, but not including, 1.30.8; 2.0 up to, but not including, 2.2.4 | 1.30.8, 2.2.4 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- LowSome restricted data can be read.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 6.0 | Medium | CNA (mongodb.com) |
| CVSS 3.1 | 5.9 | Medium | CNA (mongodb.com) |
| CVSS 3.1 | 7.1 | High | NVD |
Official description
The MongoDB C Driver's legacy GridFS API accepts malformed file metadata from the database without adequate validation. Crafted documents in a GridFS collection may cause any application that reads those files via the legacy API to either crash (via a division-by-zero) or silently leak process memory contents (via an out-of-bounds read).
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Validation of Specified Index, Position, or Offset in Input
The product receives input that is expected to specify an index, position, or offset into an indexable resource such as a buffer or file, but it does not validate or incorrectly validates that the specified index/position/offset has the required properties.
More Improper Validation of Specified Index, Position, or Offset in Input vulnerabilities (CWE-1285)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Other vulnerabilities in C Driver
- 7.5 High severity
- 7.1 High severity
- 7.5 High severity
- 7.5 High severity
- 7.6 High severity
- 7.4 High severity
Recent Improper Validation of Specified Index, Position, or Offset in Input vulnerabilities
- 8.6 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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