CVE-2026-104364: 
IBM Db2 vulnerability analysis and mitigation

CVE-2026-104364 is an improper input validation vulnerability in IBM Db2 that allows a local attacker to cause a denial of service. It affects IBM Db2 versions 11.5.0 through 11.5.9 and 12.1.0 through 12.1.5. The vulnerability was published on October 12, 2026, with a patch available as of the same date. It carries a CVSS v3.1 base score of 3.3 (Low) (GitHub Advisory, IBM Support).

The root cause is classified as CWE-20 (Improper Input Validation): IBM Db2 fails to adequately validate input data, which can be leveraged by a local, low-privileged attacker to trigger abnormal database behavior. The attack vector is local, requires low privileges, no user interaction, and has low attack complexity, meaning an authenticated local user can supply malformed input to affected Db2 components to induce a denial of service condition. The integrity impact is rated low, while confidentiality and availability impacts are listed as none in the CVSS scoring, though the described effect is a denial of service (GitHub Advisory). No public proof-of-concept or detailed technical write-up has been identified at this time.

Successful exploitation allows a local attacker with low-level privileges to crash or make the IBM Db2 database service unavailable, disrupting database operations for dependent applications and users. There is a low integrity impact noted in the CVSS scoring, suggesting limited potential for unauthorized data modification. Confidentiality is not impacted, and lateral movement potential is minimal given the local-only attack vector (GitHub Advisory, IBM Support).

There is no evidence of active in-the-wild exploitation or a publicly available proof-of-concept for CVE-2026-104364. The EPSS score is 0.0, indicating a very low probability of exploitation in the near term. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, and NVD's SSVC assessment confirms no known exploitation and non-automatable attack conditions (GitHub Advisory).

IBM has released a patch addressing this vulnerability; users should upgrade IBM Db2 to a version beyond 11.5.9 (in the 11.5.x line) or beyond 12.1.5 (in the 12.1.x line). As a compensating control, restrict local system access to the Db2 host to only trusted users with a legitimate operational need. Monitoring for unexpected Db2 process terminations or service unavailability can help detect exploitation attempts (IBM Support, GitHub Advisory).