CVE-2026-5038
Expressjs Multer 2.0.0 – 2.2.0
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:LSummary
CVE-2026-5038 is a medium-severity Incomplete Cleanup (CWE-459) vulnerability in Expressjs Multer. Its CVSS base score is 5.3 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Data from Local System (T1005); ranked at the 20th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-14 (Non-persistence) — see the control section below for these in your framework.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-36728
Vulnerability Data
Impact: multer versions 2.0.0-alpha.1 through 2.1.1 and 3.0.0-alpha.1 are vulnerable to a Denial of Service when using diskStorage. Aborted or malformed multipart uploads leave orphaned partial files on disk because the Readable.pipe() call does not propagate the stream destroy signal…
more
to the underlying fs.WriteStream. An attacker can exhaust disk space by triggering many aborted uploads, with no application bug required. Patches: Users should upgrade to multer 2.2.0 (2.x line) or 3.0.0-alpha.2 (3.x prerelease). Both versions track in-flight write streams and clean them up on the abort path. Workarounds: None.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V6.4.1
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation can discover incomplete cleanup through dynamic analysis or resource-leak testing.
Non-persistence mechanisms explicitly initiate resources in a known state and terminate them, directly enforcing cleanup.
Session termination forces explicit release of session-related temporary resources.
Preventing unintended information transfer through shared resources requires complete cleanup of those resources.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure-development practices and coding standards normally require proper resource release and cleanup.
Life-cycle management encompasses disposal of temporary resources but does not specifically target runtime cleanup bugs.
Explicitly calls for removing sensitive data after use, directly addressing one class of incomplete cleanup.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Explicitly requires secure deletion of temporary or residual data, directly addressing incomplete cleanup.
SDLC practices include cleanup steps, yet the weakness can still occur if those steps are omitted.
Secure-coding rules can mandate explicit cleanup of temporary resources, but do not guarantee it.
Change-management processes may require cleanup verification, but the control itself does not address the weakness.