OMENWAVE modelled vulnerability-chaining pathways

CVE-2021-27877

An issue was discovered in Veritas Backup Exec before 21.2. It supports multiple authentication schemes: SHA authentication is one of these. This authentication scheme is no longer used in current versions of the product, but hadn't yet been disabled. An attacker could remotely exploit this scheme to gain unauthorized access to an Agent and execute privileged commands.

9.8
CVSS Critical
64.9%
EPSS p99
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
INITIAL_ACCESS
Requires
NONE access, NETWORK vector
Grants
USER access
Capabilities
code execution
Model confidence
medium · CVSS 3.1
Top plausible next hops
CVE-2025-49704INITIAL_ACCESS → 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-2022-41040INITIAL_ACCESS → 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-2020-0688INITIAL_ACCESS → 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-2021-27878INITIAL_ACCESS → EXECUTIONhigh plausibility · KEV

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

An issue was discovered in Veritas Backup Exec before 21.2. The communication between a client and an Agent requires successful authentication, which…

CVE-2021-34527INITIAL_ACCESS → 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…

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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-2021-27877