Security Resilience

CVE-2026-77090

XXE

XXE
Published
13 October 2026
Modified
14 October 2026
CVSS Score v4 8.7
Click a component to see what it means
Raw vectorCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/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 0.0033 25th percentile
Risk Priority 44 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-2026-77090 is a high-severity Improper Restriction of XML External Entity Reference (CWE-611) vulnerability in Commvault (inferred from references). Its CVSS base score is 8.7 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Data from Local System (T1005); ranked at the 25th 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 CM-6 (Configuration Settings) and SA-11 (Developer Testing and Evaluation) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A02:2025 Security Misconfiguration

EU & UK References

Vulnerability Data

CVFS contained an XML external entity (XXE) reference handling issue affecting information dislcosure. Software customers upgrade to resolved maintenance release. Update CVFS.

CWE(s)
CWE-611

Related Threats

MITRE ATT&CK Enterprise Techniques

T1005 Data from Local System Collection
Adversaries may search local system sources, such as file systems, configuration files, local databases, virtual machine files, or process memory, to find files of interest and sensitive data prior to Exfiltration.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2024-3930Shared CWE-611
CVE-2024-4690Shared CWE-611
CVE-2025-10713Shared CWE-611
CVE-2024-21255Shared CWE-611
CVE-2023-6194Shared CWE-611
CVE-2024-25606Shared CWE-611
CVE-2025-66370Shared CWE-611
CVE-2023-46802Shared CWE-611
CVE-2026-44618Shared CWE-611
CVE-2024-27266Shared CWE-611

Affected Assets

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

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)
  • V1.5.1
  • V15.3.2

Mitigating Controls (NIST 800-53 r5) AI

CM-6 Configuration Settings partial match

Secure configuration settings can disable external entity processing in XML parsers.

SA-11 Developer Testing and Evaluation partial match

Developer testing can discover XXE flaws through targeted XML parsing tests.

SI-10 Information Input Validation partial match

Input validation can reject or sanitize XML containing external entity references.

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-01 mostly match
blocks

Hardened XML parser configurations directly disable external entity resolution.

PR.PS-06 mostly match
blocks

Secure SDLC practices include input validation and safe XML parser configuration that prevent XXE.

ID.RA-01 partial match
blocks

Vulnerability scanning can discover XXE flaws but does not prevent their introduction in code.

PR.PS-02 partial match
blocks

Patching eliminates XXE-vulnerable parser versions but is only one aspect of software maintenance.

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 catches XXE via static analysis and dynamic XML fuzzing.

A.8.28 Secure coding partial match
prevents

Secure coding standards require disabling DTDs and external entities in XML processing.

A.8.8 Management of technical vulnerabilities partial match
finds

REACH: a disclosure-reach control sees only instances that carry a vendor-published flaw, so `finds` is at most `partial` (rule, 2026-10-17).

References