Cyber Resilience

CVE-2026-100891

Published
28 September 2026
Modified
28 September 2026
CVSS Score v4 5.5
Click a component to see what it means
Raw vectorCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P/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 0.0029 20th percentile
Risk Priority 38 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-2026-100891 is a medium-severity Encoding Error (CWE-172) vulnerability in Weitongli (inferred from references). Its CVSS base score is 5.5 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Obfuscated Files or Information (T1027); ranked at the 20th 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) and SI-15 (Information Output Filtering) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

A vulnerability has been found in Trusted Domain Project OpenDMARC up to 1.4.2. Affected by this issue is the function opendmarc_policy_query_dmarc in the library libopendmarc/opendmarc_policy.c of the component Internationalized Domain Name Handler. Such manipulation leads to encoding error. It is…

more

possible to launch the attack remotely. The exploit has been disclosed to the public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.

CWE(s)
CWE-172

Related Threats

MITRE ATT&CK Enterprise Techniques

T1027 Obfuscated Files or Information Stealth
Adversaries may attempt to make an executable or file difficult to discover or analyze by encrypting, encoding, or otherwise obfuscating its contents on the system or in transit.
attack.mitre.org →
T1059 Command and Scripting Interpreter Execution
Adversaries may abuse command and script interpreters to execute commands, scripts, or binaries.
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 →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2024-48909Shared CWE-172
CVE-2026-42926Shared CWE-172
CVE-2025-27110Shared CWE-172
CVE-2026-48784Shared CWE-172
CVE-2025-12758Shared CWE-172

Affected Assets

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

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

SI-10 Information Input Validation partial match

Input validation can reject or normalize improperly encoded data before it is processed.

SI-15 Information Output Filtering partial match

Output filtering enforces correct encoding or escaping of data leaving the system.

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 correct data encoding to avoid injection and corruption flaws.

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 includes input/output validation and encoding practices that reduce encoding errors.

A.8.26 Application security requirements partial match
prevents

Application security requirements can mandate proper encoding/decoding to prevent data corruption or injection.

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

Secure system architecture and engineering principles address data handling and transformation correctness.

A.8.28 Secure coding partial match
prevents

Secure coding explicitly requires correct character encoding and output escaping to avoid CWE-172.

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

Security testing in development can detect encoding flaws before deployment.

References