Db2: Stack-based Buffer Overflow
CVE-2026-86093 is a high-severity stack-based buffer overflow vulnerability in Db2 from IBM, with a CVSS 3.1 base score of 7.5 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. Affected Db2 versions: 11.5.0 through 11.5.9; 12.1.0 through 12.1.5. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.51% 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
- Check which version of Db2 you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on ibm.com for workarounds and exact fixed builds.
Affected products and versions
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
- HighSuccess depends on conditions outside the attacker's control.
- 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
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by CNA (us.ibm.com).
Official description
IBM Db2 11.5.0 through 11.5.9, and 12.1.0 through 12.1.5 could allow an attacker with the ability to control or impersonate a DRDA server endpoint to execute arbitrary commands on Db2 clients due to a stack-based buffer overflow that improperly copies user-controlled data into a fixed-size stack buffer without bounds checking.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Stack-based Buffer Overflow
The product writes past the end of a buffer that was allocated on the stack.
How developers prevent this class of flaw
- Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.
- Use an abstraction library to abstract away risky APIs. Not a complete solution.
- Implement and perform bounds checking on input.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Other vulnerabilities in Db2
- 7.7 High severity
- 8.8 High severity
- 7.5 High severity
- 8.1 High severity
- 7.1 High severity
- 7.5 High severity
Recent Stack-based Buffer Overflow vulnerabilities
- 7.0 High severity
- 7.8 High severity
- 7.5 High severity
- 7.5 High severity
- 8.4 High severity
- 7.6 High severity
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