CVE-2026-40200
Raw vector
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:HCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2026-40200 is a high-severity Always-Incorrect Control Flow Implementation (CWE-670) vulnerability in Libc (inferred from references). Its CVSS base score is 8.1 (High).
Operationally, ranked at the 6th 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 SA-15 (Development Process, Standards, and Tools) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-40200 is a stack-based memory corruption vulnerability affecting musl libc versions 0.7.10 through 1.2.6. The issue arises during qsort operations on very large arrays, where the number of elements must exceed about seven million—the 32nd Leonardo number on 32-bit platforms—or the 64th Leonardo number on 64-bit platforms, which is not practical. It stems from incorrectly implemented double-word primitives and is classified under CWE-670.
The vulnerability carries a CVSS v3.1 base score of 8.1 (AV:L/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H). Local attackers require no privileges but must overcome high attack complexity to trigger it, potentially achieving high impacts on confidentiality, integrity, and availability with a change in scope through memory corruption.
Advisories and patches are referenced in the musl libc release notes at https://musl.libc.org/releases.html and the oss-security mailing list announcement at https://www.openwall.com/lists/oss-security/2026/04/10/13 or http://www.openwall.com/lists/oss-security/2026/04/10/13. The vulnerability was published on 2026-04-10.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-21496
Vulnerability Data
An issue was discovered in musl libc 0.7.10 through 1.2.6. Stack-based memory corruption can occur during qsort of very large arrays, due to incorrectly implemented double-word primitives. The number of elements must exceed about seven million, i.e., the 32nd Leonardo…
more
number on 32-bit platforms (or the 64th Leonardo number on 64-bit platforms, which is not practical).
- CWE(s)
Related Threats
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V9.2.1
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation at post-design stages directly exercises control-flow paths and reveals mismatches between implemented and intended behavior.
Requiring a documented development process and supporting tools reduces the chance that incorrect control-flow logic is introduced in the first place.
Flaw identification and remediation processes can locate and correct control-flow errors once they manifest as incorrect runtime behavior.
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 SDLC practices directly prevent incorrect control-flow implementations via reviews, testing, and static analysis.
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.
Secure development lifecycle processes can catch incorrect control-flow logic during design and code review.
Secure coding standards and reviews directly target flawed control-flow implementations.
Security testing in development and acceptance can detect paths that deviate from intended logic.
Change-management gates may prevent deployment of flawed logic but do not address the coding defect itself.