OMENWAVE modelled vulnerability-chaining pathways

CVE-2021-27876

An issue was discovered in Veritas Backup Exec before 21.2. The communication between a client and an Agent requires successful authentication, which is typically completed over a secure TLS communication. However, due to a vulnerability in the SHA Authentication scheme, an attacker is able to gain unauthorized access and complete the authentication process. Subsequently, the client can execute data management protocol commands on the authenticated connection. By using crafted input parameters in one of these commands, an attacker can access an arbitrary file on the system using System privileges.

8.1
CVSS High
13.5%
EPSS p96
YES
In CISA KEV
YES
Ransomware-linked

Data as of 2 Nov 2026 · NVD, CISA KEV, EPSS

Why chaining, at machine speed

Defenders still triage vulnerabilities one CVE at a time, while increasingly automated attackers combine them at machine speed. Omenwave models the plausible pathways by which this CVE could be chained with others — surfacing them for research and awareness, with evidence for each step.

Modelled capability profile
Kill-chain stage
RECON
Requires
USER access, NETWORK vector
Grants
USER access
Capabilities
information disclosuredata tampering
Model confidence
medium · CVSS 3.1
Top plausible next hops
CVE-2025-49704RECON → EXECUTIONmedium plausibility · KEV

The access level the source grants already meets or exceeds the access level the destination requires — the position carries over.

Improper control of generation of code ('code injection') in Microsoft Office SharePoint allows an authorized attacker to execute code over a network.

CVE-2022-41040RECON → EXECUTIONmedium plausibility · KEV

The access level the source grants already meets or exceeds the access level the destination requires — the position carries over.

Microsoft Exchange Server Elevation of Privilege Vulnerability

CVE-2020-0688RECON → EXECUTIONmedium plausibility · KEV

The access level the source grants already meets or exceeds the access level the destination requires — the position carries over.

A remote code execution vulnerability exists in Microsoft Exchange software when the software fails to properly handle objects in memory, aka 'Micros…

CVE-2021-34527RECON → EXECUTIONmedium plausibility · KEV

The access level the source grants already meets or exceeds the access level the destination requires — the position carries over.

A remote code execution vulnerability exists when the Windows Print Spooler service improperly performs privileged file operations. An attacker who s…

CVE-2025-49113RECON → EXECUTIONmedium plausibility · KEV

The access level the source grants already meets or exceeds the access level the destination requires — the position carries over.

Roundcube Webmail before 1.5.10 and 1.6.x before 1.6.11 allows remote code execution by authenticated users because the _from parameter in a URL is n…

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Modelled plausible chaining potential derived from public CVE metadata (CVSS, CWE, CPE). Not a confirmed real-world exploit chain and contains no exploitation detail. For research and awareness only.

Methodology · Interactive explorer · JSON: /cve/CVE-2021-27876