Cyber Resilience

CVE-2026-89087

Published
10 September 2026
Modified
10 September 2026
CVSS Score v3.1 7.3
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
EPSS Score 0.0019 8th percentile
Risk Priority 54 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2026-89087 is a high-severity Improper Following of Specification by Caller (CWE-573) vulnerability in Osv (inferred from references). Its CVSS base score is 7.3 (High).

Operationally, ranked at the 8th 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.

EU & UK References

Vulnerability Data

The cstruct package before 6.3.0 for OCaml mishandles indexes.

CWE(s)
CWE-573

Related Threats

CVEs Like This One

CVE-2026-41583Shared CWE-573
CVE-2025-69287Shared CWE-573
CVE-2026-59998Shared CWE-573
CVE-2025-21601Shared CWE-573
CVE-2025-46330Shared CWE-573
CVE-2025-69202Shared CWE-573
CVE-2026-28498Shared CWE-573

Affected Assets

Osv
—
inferred from references and description; NVD did not file a CPE for this CVE

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

SA-11 Developer Testing and Evaluation partial match

Developer testing and evaluation can discover cases where callers fail to follow required specifications or APIs.

SA-15 Development Process, Standards, and Tools partial match

Requiring a documented development process and standards reduces the chance that callers will deviate from language, framework, or protocol specifications.

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.

PR.PS-06 partial match
prevents

Secure SDLC practices directly enforce correct adherence to language, framework, protocol and platform specifications during implementation.

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.

A.8.25 Secure development life cycle partial match
prevents

Secure development life cycle mandates adherence to language, framework and protocol specifications, directly reducing improper caller behavior.

A.8.26 Application security requirements partial match
prevents

Application security requirements explicitly capture specification compliance obligations that callers must follow.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure system architecture and engineering principles include specification adherence as a design constraint.

A.8.28 Secure coding partial match
prevents

Secure coding standards enforce correct use of APIs, protocols and language features, mitigating caller specification violations.

A.8.29 Security testing in development and acceptance partial match
finds

Security testing can detect specification non-compliance but does not itself prevent the weakness.

A.8.32 Change management partial match
prevents

Change management can catch specification drift during updates but is not a primary mitigation.

References