What is the CVSS score of CVE-2021-28973?

CVE-2021-28973 has a CVSS 3.1 base score of 4.9 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N. EPSS exploitation probability: 0.9%.

Is there a public PoC exploit available for CVE-2021-28973?

Yes, a public proof-of-concept exploit is available for CVE-2021-28973. Prioritise patching immediately. EPSS: 0.9%.

Perforce CVE-2021-28973

MEDIUM

Improper Restriction of XML External Entity Reference (CWE-611)

2021-04-13 cve@mitre.org

XXE Perforce Helix Alm

4.9

CVSS 3.1 · NVD

View

Vulnerability Assessment

Weakness	CWE CWE-611 OWASP Top 10:2025 A02:2025 - Security Misconfiguration ASVS 5.0 V13 - Configuration XML external entity prevention MITRE ATT&CK 2 techniques across 2 tactics: Initial Access, Collection The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. Sign in to read
Impact	CVSS score of 4.9 (MEDIUM). Attack characteristics: network attack vector, low complexity, high privileges required, no user interaction not required. Public proof-of-concept exploit code is available.
Exploit ScenarioDerived	A remote attacker could read arbitrary files or perform SSRF through XML processing by sending crafted requests to the affected application.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).

No patch listed yet 0.9% exploitation probability (EPSS)

Get an e-mail when this CVE is exploited, patched or re-scored. Free account.

Alert me

AnalysisAI

The XML Import functionality of the Administration console in Perforce Helix ALM 2020.3.1 Build 22 accepts XML input data that is parsed by insecurely configured software components, leading to XXE. Rated medium severity (CVSS 4.9), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Disable external entity processing in XML parsers, use JSON instead of XML where possible.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified as XML External Entity (XXE) (CWE-611), which allows attackers to read arbitrary files or perform SSRF through XML processing. The XML Import functionality of the Administration console in Perforce Helix ALM 2020.3.1 Build 22 accepts XML input data that is parsed by insecurely configured software components, leading to XXE attacks. Affected products include: Perforce Helix Alm.

Know when Perforce gets its next vulnerability

Watch products and get an email when something new is published
Check this CVE against your own stack and servers
Exploit and PoC references, threat intelligence from 22 sources

Continue with Google Continue with GitHub

No credit card · 7-day full trial

Severity by source

NVD PRIMARY 4.9 MEDIUM

AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

High

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

None

DescriptionNVD

Threat Intelligence Overview

EPSS Score

0.9%

Top 45% exploitable

Exploit

POC

Public exploit code exists

Data Quality

2 sources

Confidence: Low

NVD

CVE.org

EPSS

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity MEDIUM

CISA KEV No

Public POC Yes

EPSS 0.9%

Patch available No

Active threat No

Deciding rule

MEDIUM severity (CVSS 4.0-6.9)

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived

Scheduled

Exploitation· derived

Poc

System Exposure· derived

Open

Automatable· derived

Human Impact· derived

Medium

Priority Score

Low Medium High Critical

KEV: 0

EPSS: +1

CVSS: +24

PoC: +20

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

XML External Entity Injection HIGH

XML External Entity (XXE) attacks exploit XML parsers that process Document Type Definitions (DTDs) without proper restrictions.

Affected Products (CPE)NVD

cpe:2.3:a:perforce:helix_alm:2020.3.1:build_22:*:*:*:*:*:*

More in Perforce

View all

CVE-2015-8965 CRITICAL Act Now

9.8 Apr 06

Rogue Wave JViews before 8.8 patch 21 and 8.9 before patch 1 allows remote attackers to execute arbitrary Java code that

CVE-2026-85978 CRITICAL Act Now

10.0 Sep 09

Remote code execution in Perforce Akana API Platform allows unauthenticated attackers to run arbitrary code on the Polic

CVE-2024-3930 CRITICAL Act Now

9.8 Jul 30

In versions of Akana API Platform prior to 2024.1.0 a flaw resulting in XML External Entity (XXE) was discovered. Rated

CVE-2023-45849 CRITICAL Act Now

9.8 Nov 08

An arbitrary code execution which results in privilege escalation was discovered in Helix Core versions prior to 2023.2.

CVE-2026-100102 CRITICAL Act Now

9.5 Oct 05

Unauthenticated remote code execution is possible in Perforce P4 Search container images prior to 2026.4.2 due to an exp

CVE-2026-103510 CRITICAL Act Now

9.5 Oct 05

Perforce P4 Search before 2026.4.2 fails open when its service authentication token is blank, so an unauthenticated remo

CVE-2026-109758 CRITICAL Act Now

9.3 Oct 13

Unauthorized SCIM API access in Perforce Helix Authentication Service (HAS) versions 2022.1 through 2025.2 arises from a

CVE-2026-115731 CRITICAL Act Now

9.4 Nov 03

Remote code execution in the report-processing code of Puppet Server (shipped in Puppet Enterprise) lets a client holdin

CVE-2026-89212 CRITICAL Act Now

9.2 Sep 11

XML external entity (XXE) injection in Perforce's Akana API Platform allows remote unauthenticated attackers to abuse im

CVE-2026-115732 CRITICAL Act Now

9.0 Nov 03

Incorrect authorization in trapperkeeper-authorization, used by Puppet Server and Puppet Enterprise, lets a client holdi

CVE-2026-6043 HIGH This Week

8.8 Apr 24

Helix Core Server (P4D) before 2026.1 ships with insecure default configurations allowing remote unauthenticated attacke

CVE-2026-103509 HIGH This Week

8.5 Oct 15

Cleartext credential disclosure in P4 Search (formerly Helix Search) 2026.4.2 and earlier allows an authenticated admini

Same weakness CWE-611 – Improper Restriction of XML External Entity Reference

View all

CVE-2019-9670 CRITICAL POC

9.8

CVE-2025-58360 CRITICAL POC

9.8

CVE-2025-2775 CRITICAL POC

9.3

CVE-2025-2776 CRITICAL POC

9.3

CVE-2017-12629 CRITICAL POC

9.8

CVE-2016-9563 MEDIUM POC

6.5

CVE-2012-3363 CRITICAL POC

9.1

CVE-2016-4264 HIGH POC

8.6

Same technique XXE

View all

CVE-2013-5014 HIGH POC

7.5

CVE-2015-0923 MEDIUM POC

5.0

CVE-2014-0644 HIGH POC

7.8

Search Externally

GitHub PoC

Exploit-DB PacketStorm Snyk Rapid7 Nuclei Templates Trickest PoC

Back