Cyber Resilience

CVE-2026-91948

Memory Safety

Public PoCMemory Safety
Published
15 September 2026
Modified
16 September 2026
CVSS Score v4 7.7
Click a component to see what it means
Raw vectorCVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS Score 0.0065 49th percentile
Risk Priority 32 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-2026-91948 is a high-severity Wrap or Wraparound (CWE-191) vulnerability. Its CVSS base score is 7.7 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 49th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SA-8 (Security and Privacy Engineering Principles) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

FreeRDP versions before 3.31.0 contain an out-of-bounds write vulnerability in server-side static virtual channel handling when CHANNEL_OPTION_SHOW_PROTOCOL is enabled. Authenticated clients can queue oversized channel messages that cause buffer underflow and corrupt heap memory including live pointers, potentially enabling code…

more

execution.

CWE(s)
CWE-191

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 →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2024-52986Shared CWE-191
CVE-2026-42542Shared CWE-191
CVE-2023-33158Shared CWE-191
CVE-2026-73433Shared CWE-191
CVE-2026-27297Shared CWE-191
CVE-2024-28945Shared CWE-191
CVE-2023-28293Shared CWE-191
CVE-2023-21708Shared CWE-191
CVE-2024-50596Shared CWE-191
CVE-2024-37974Shared CWE-191

Affected Assets

—
FreeRDP
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 static/dynamic analysis directly find integer underflow defects before code is released.

SA-8 Security and Privacy Engineering Principles partial match

Security engineering principles require use of safe arithmetic constructs or language features that structurally eliminate integer underflow during subtraction.

SI-10 Information Input Validation partial match

Input validation can reject or sanitize values that would cause a subtraction to underflow the representable range.

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.

ID.RA-01 partial match
prevents

Vulnerability scanning and code analysis can surface underflow flaws after they are introduced.

PR.PS-02 partial match
prevents

Routine patching can remediate known underflow bugs once they are discovered in deployed software.

PR.PS-06 partial match
prevents

Secure SDLC practices directly prevent integer underflow defects via input validation, bounds checking, 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.

A.8.25 Secure development life cycle partial match
prevents

Secure development lifecycle mandates input validation and arithmetic checks that prevent integer underflow.

A.8.26 Application security requirements partial match
prevents

Application security requirements include bounds checking and safe arithmetic to avoid underflow conditions.

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

Secure architecture principles require defensive coding patterns that mitigate integer wraparound risks.

A.8.28 Secure coding partial match
prevents

Secure coding standards directly prescribe safe integer handling and overflow/underflow prevention.

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

Security testing in development catches integer underflow defects before release.

References