Cyber Resilience

CVE-2026-55830

Published
08 July 2026
Modified
10 July 2026
CVSS Score v3.1 8.3
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:L
EPSS Score 0.0040 34th 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-2026-55830 is a high-severity Incomplete List of Disallowed Inputs (CWE-184) vulnerability. Its CVSS base score is 8.3 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 34th 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 SI-10 (Information Input Validation) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

RestrictedPython is a tool that helps to define a subset of the Python language which allows to provide a program input into a trusted environment. Prior to 8.3, check_function_argument_names() rejected protected guard hook names for regular, variadic, and keyword-only arguments…

more

but omitted positional-only arguments, allowing __getattr__, _getitem_, _write_, or _print_ to be shadowed by a local parameter and bypass the embedding application's access policy. This issue is fixed in version 8.3.

CWE(s)
CWE-184

Related Threats

MITRE ATT&CK Enterprise Techniques

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-62203Shared CWE-184
CVE-2025-71320Shared CWE-184
CVE-2026-53864Shared CWE-184
CVE-2023-45593Shared CWE-184
CVE-2026-56315Shared CWE-184
CVE-2026-34177Shared CWE-184
CVE-2026-71259Shared CWE-184
CVE-2026-86199Shared CWE-184
CVE-2026-44993Shared CWE-184
CVE-2026-32022Shared CWE-184

Affected Assets

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 2 hardening rules · 1 OS baseline
Validate
Prove the fix (OWASP ASVS)
  • V3.5.2
  • V4.4.2
  • V16.2.5

Mitigating Controls (NIST 800-53 r5) AI

SI-10 Information Input Validation good match

SI-10 requires validity checks on inputs, which structurally replaces incomplete deny-lists with complete allow-list or sanitization logic.

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 require complete, positive input validation instead of incomplete denylists.

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.8.26 Application security requirements partial match
prevents

Application security requirements can mandate complete input validation rules, but the control itself does not prescribe how to build those rules.

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

Secure architecture principles include robust input validation design, yet the control is broader than this single weakness.

A.8.28 Secure coding partial match
prevents

Secure coding standards directly require exhaustive allow-lists or complete deny-lists for inputs, addressing the root cause of incomplete disallowed-input lists.

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

Security testing can discover missing input checks, but does not prevent the weakness during development.

References