CVE-2026-9366· NVD / CVE Program· CNA VulDB

NousResearch hermes-agent prompt_builder.py _scan_context_content injection

A vulnerability was found in NousResearch hermes-agent 2026.4.23. The impacted element is the function _scan_context_content of the file agent/prompt_builder.py. The manipulation results in injection. The attack may be performed from remote. The exploit has been made public and could be used. The vendor was contacted early about this disclosure but did not respond in any way.

MediumCVSS 5.5 · v4.0—No exploit Fix available

Pre-auth

Published: May 24, 2026
Updated: Jul 23, 2026
EPSS: 0.5% · 42th percentile
CWE: CWE-74

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Action score

Monitor

Low priority for now.

CVSS: 22 / 40 · 5.5 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.5%

CISA SSVC decision

Exploitation: proof of concept
Automatable: yes
Technical impact: partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: —
CNA · VulDB: 6.9; NVD has not scored this yet; the score shown is the CNA’s.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Affected systems

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Versions reported by the vendor

Affected version ranges reported by the assigning authority (VulDB). Independent of NVD's CPE analysis and usually ahead of it.

NousResearch hermes-agent
- 2026.4.23affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
PyPI	hermes-agent	before 0.15.0	0.15.0

Same product

nousresearch: all records

Other highest-scoring records for the same primary product.

CVE-2026-82021Hermes Agent 0.18.2 < 0.19.0 MCP Catalog Supply Chain RCE via Mutable Branch Reference
36Monitor
CVE-2026-71963Hermes Agent 0.18.2 - 0.21.0 RCE via git core.fsmonitor Config Injection
34Monitor
CVE-2026-53869Hermes Agent < 0.16.0 - DNS Rebinding Bypass via WebSocket Endpoints
34Monitor
CVE-2026-82020Hermes Agent 0.16.0 < 0.17.0 Credential Store Overwrite via File-Write Tool
30Monitor
CVE-2026-85105NousResearch hermes-agent Session Management s71.py _sess_nowait authorization
27Monitor
CVE-2026-53870Hermes Agent < 0.16.0 - Sensitive File Permission Vulnerability in Store Files
27Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
PyPI:hermes-agent	0.15.0	Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Eric-i (VulDB User)reporter
VulDB CNA Teamcoordinator

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

CVE-2026-93530 days apartNousResearch hermes-agent Skills Guard Multi-Word Prompt skills_guard.py injection
22Monitor
CVE-2026-93540 days apartNousResearch hermes-agent Slack Agent/Mattermost Agent escape output
22Monitor
CVE-2026-102208 days apartNousResearch hermes-agent skills_tool.py skill_view injection
22Monitor
CVE-2026-102218 days apartNousResearch hermes-agent run_agent.py _compress_context injection
22Monitor
CVE-2026-102228 days apartNousResearch hermes-agent config.py _sanitize_env_lines injection
11Monitor
CVE-2026-102238 days apartNousResearch hermes-agent memory_tool.py _scan_memory_content injection
8Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

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Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
No account or password is required.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: None
Scope: X

Weakness class (CWE)

CWE-74 · Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P/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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

Noroxi analysis

No Noroxi analysis for this record yet

We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.

We use this product, ask for help

Change log

Fix✗ → ✓Sep 28, 2026, 10:47 PM UTC

For records you follow, these changes also arrive as notifications. →

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records