Cyber Resilience

CVE-2026-51080

XXE in Proxmox Libpve-Storage-Perl 8.3.7 … 9.1.1

XXE
Published
17 July 2026
Modified
11 August 2026
Patch / advisory
View advisory
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 0.0052 43th percentile
Risk Priority 71 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-2026-51080 is a critical-severity Improper Restriction of XML External Entity Reference (CWE-611) vulnerability in Proxmox Libpve-Storage-Perl. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Data from Local System (T1005); ranked at the 43th 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

libpvestorage-perl v9.1.1 and libpve-storage-perl v8.3.7 were discovered to contain an XML External Entity (XXE) vulnerability.

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 →
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 →
T1213 Data from Information Repositories Collection
Adversaries may leverage information repositories to mine valuable information.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-57538Same product class: hypervisor / virtualization
CVE-2023-46854Same product class: hypervisor / virtualization
CVE-2025-57539Same product class: hypervisor / virtualization
CVE-2025-57540Same product class: hypervisor / virtualization
CVE-2023-43320Same product class: hypervisor / virtualization
CVE-2025-31487Shared CWE-611
CVE-2023-35892Shared CWE-611
CVE-2023-45192Shared CWE-611
CVE-2023-6147Shared CWE-611
CVE-2023-26057Shared CWE-611

Affected Assets

proxmox
libpve-storage-perl
8.3.7, 9.1.1

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 good match

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

SA-11 Developer Testing and Evaluation good match

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

SI-10 Information Input Validation good 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.

ID.RA-01 partial match
prevents

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

PR.PS-01 partial match
prevents

Hardened XML parser configurations directly disable external entity resolution.

PR.PS-02 partial match
prevents

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

PR.PS-06 partial match
prevents

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

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 life cycle mandates input validation and entity handling that directly prevents XXE.

A.8.26 Application security requirements partial match
prevents

Application security requirements explicitly call for disabling external entity processing in XML parsers.

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

Secure architecture principles include safe parser configuration that mitigates external entity risks.

A.8.28 Secure coding partial match
prevents

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

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

Security testing in development catches XXE via static analysis and dynamic XML fuzzing.

A.8.8 Management of technical vulnerabilities partial match
finds

Vulnerability management identifies and patches XML libraries with unsafe default entity settings.

References