Cyber Resilience

CVE-2025-55398

Published
22 August 2025
Modified
17 June 2026
CVSS Score v3.1 9.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0037 30th percentile
Risk Priority 71 floored blend · peak EPSS

Summary

CVE-2025-55398 is a critical-severity Improper Validation of Specified Quantity in Input (CWE-1284) vulnerability. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 30th 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.

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-2025-55398 affects the mouse07410 asn1c library through version 0.9.29 (dated 2025-03-20), a fork of vlm asn1c. The vulnerability resides in UPER (Unaligned Packed Encoding Rules) decoders generated by asn1c, which fail to enforce INTEGER constraints when the bound is positive and exceeds 32 bits in length. This flaw, tracked under CWE-1284, enables the processing of incorrect or malicious input and carries a CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), indicating critical severity.

Remote attackers require no privileges, authentication, or user interaction to exploit this vulnerability over the network with low complexity. Successful exploitation allows processing of malformed input in affected decoders, potentially leading to high impacts on confidentiality, integrity, and availability as scored by CVSS.

Details on the issue, including potential mitigations or patches, are discussed in the GitHub advisory at https://github.com/mouse07410/asn1c/issues/222.

EU & UK References

Vulnerability Data

An issue was discovered in mouse07410 asn1c thru 0.9.29 (2025-03-20) - a fork of vlm asn1c. In UPER (Unaligned Packed Encoding Rules), asn1c-generated decoders fail to enforce INTEGER constraints when the bound is positive and exceeds 32 bits in length,…

more

potentially allowing incorrect or malicious input to be processed.

CWE(s)
CWE-1284

Related Threats

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
attack.mitre.org →
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 →
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
attack.mitre.org →
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
attack.mitre.org →
T1212 Exploitation for Credential Access Credential Access
Adversaries may exploit software vulnerabilities in an attempt to collect credentials.
attack.mitre.org →
T1499 Endpoint Denial of Service Impact
Adversaries may perform Endpoint Denial of Service (DoS) attacks to degrade or block the availability of services to users.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2024-8558Shared CWE-1284
CVE-2023-27941Shared CWE-1284
CVE-2025-8320Shared CWE-1284
CVE-2025-14689Shared CWE-1284
CVE-2026-2403Shared CWE-1284
CVE-2025-48507Shared CWE-1284
CVE-2025-36407Shared CWE-1284
CVE-2023-20515Shared CWE-1284
CVE-2025-10259Shared CWE-1284
CVE-2026-33349Shared CWE-1284

Affected Assets

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V6.7.2
  • V1.4.2
  • V2.1.1
  • V2.2.1

Mitigating Controls (NIST 800-53 r5) AI

SI-10 Information Input Validation good match

SI-10 requires validity checks on information inputs, directly stopping acceptance of malformed quantities before they can be used.

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 mostly match
prevents

Secure SDLC practices directly require proper quantity/length validation in input handling.

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.8.29 Security testing in development and acceptance mostly match
finds

Security testing in development can detect missing quantity validation but does not itself implement the control.

A.8.25 Secure development life cycle partial match
prevents

Secure development lifecycle mandates input validation for quantity fields, directly preventing CWE-1284.

A.8.26 Application security requirements partial match
prevents

Application security requirements explicitly call for validation of size/length inputs, mitigating CWE-1284.

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

Secure architecture principles encourage robust input handling but do not specifically address quantity validation.

A.8.28 Secure coding partial match
prevents

Secure coding standards require explicit checks on numeric quantity inputs, fully addressing CWE-1284.

References