VulnerabilityPublished 27 Oct 2025

CVE-2025-33126: IBM DB2 High Performance Unload · Incorrect Calculation of Buffer Size

Affects IBM DB2 High Performance UnloadSource CVE Database V5

Not known to be exploited · CVSS 6.5 Medium.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score

6.5Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.3% chance of exploitation in 30 days – higher than 23% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 27 Oct 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
IBM DB2 High Performance Unload	Affected 5.1 – 6.5.0.0 8 affected builds	Fixed in–

AI-suggested

European organizations should implement strict access controls to limit authenticated user privileges on IBM DB2 High Performance Unload components, ensuring only trusted personnel have access. Monitoring and alerting should be enhanced to detect abnormal termination or crashes of the unload process, enabling rapid incident response. Network segmentation can reduce exposure by isolating database management interfaces from general user networks. Until IBM releases a patch, consider applying application-level input validation or workload restrictions to minimize triggering the buffer size miscalculation. Regularly audit user accounts and credentials to prevent unauthorized access. Engage with IBM support to obtain any available workarounds or interim fixes. Prepare for rapid deployment of patches once available by maintaining an up-to-date asset inventory and testing environment. Finally, incorporate this vulnerability into incident response and business continuity plans to mitigate operational impact.

Description

IBM DB2 High Performance Unload 6.1.0.3, 5.1.0.1, 6.1.0.2, 6.5, 6.5.0.0 IF1, 6.1.0.1, 6.1, 5.1, 6.1.0.3, 5.1.0.1, 6.1.0.2, 6.5, 6.5.0.0 IF1, 6.1.0.1, 6.1, 5.1, 6.1.0.3, 5.1.0.1, 6.1.0.2, 6.5, 6.5.0.0 IF1, 6.1.0.1, 6.1, 5.1, 6.1.0.3, 5.1.0.1, 6.1.0.2, 6.5, 6.5.0.0 IF1, 6.1.0.1, 6.1, and 5.1 could allow an authenticated user to cause the program to crash due to the incorrect calculation of a buffer size.

Impact

For European organizations, this vulnerability poses a risk of denial-of-service attacks on critical database unloading operations, potentially disrupting data export, backup, or migration workflows. Industries relying heavily on IBM DB2 for large-scale data processing—such as finance, telecommunications, manufacturing, and public sector—may experience operational downtime, affecting business continuity and service availability. Although confidentiality and integrity are not directly impacted, the loss of availability can hinder compliance with data handling regulations like GDPR if data processing is interrupted. Additionally, repeated crashes could lead to increased operational costs and reputational damage. The requirement for authentication limits exploitation to insiders or compromised accounts, but insider threats or credential theft remain realistic concerns. The absence of known exploits provides a window for proactive defense, but also means attackers could develop exploits once the vulnerability is publicly known.

CWE-131Incorrect Calculation of Buffer Size (opens in a new tab)
Base weaknessLikelihood of exploit: High
The product does not correctly calculate the size to be used when allocating a buffer, which could lead to a buffer overflow.
Implementation
When allocating a buffer for the purpose of transforming, converting, or encoding an input, allocate enough memory to handle the largest possible encoding. For example, in a routine that converts "&" characters to "&" for HTML entity encoding, the output buffer needs to be at least 5 times as large as the input…
Implementation
Understand the programming language's underlying representation and how it interacts with numeric calculation (CWE-681). Pay close attention to byte size discrepancies, precision, signed/unsigned distinctions, truncation, conversion and casting between types, "not-a-number" calculations, and how the language handles…
Implementation · Input Validation
Perform input validation on any numeric input by ensuring that it is within the expected range. Enforce that the input meets both the minimum and maximum requirements for the expected range.
Attack patterns
Overflow Buffers (opens in a new tab)
Buffer Overflow via Parameter Expansion (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

ibm.com/support/pages/node/7249336 (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 4 Nov 2025, 03:29 UTC

WeaknessesCWE-131

Technical details

References

Community reviews

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