CVE-2026-53870: Permission Flaw (CVSS 5.5)

Description

Hermes Agent before 0.16.0 creates response_store.db and webhook_subscriptions.json with world-readable permissions (mode 0o644), exposing conversation history and HMAC secrets to local users. Attackers with local filesystem access can read these files directly to obtain sensitive data including conversation history, tool payloads, prompts, and per-route HMAC secrets.

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CVSS v3.1 Score

5.5

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

EPSS — Exploit Prediction

0.0011

Probability of exploitation

0.01%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-276 Incorrect Default Permissions

References

Other References

https://github.com/NousResearch/hermes-agent/commit/3bace071bfadf2d2bec2ee048471a31ec920e3e8 https://github.com/NousResearch/hermes-agent/pull/30917 https://github.com/NousResearch/hermes-agent/pull/31469 https://github.com/NousResearch/hermes-agent/releases/tag/v2026.6.5 https://www.vulncheck.com/advisories/hermes-agent-sensitive-file-permission-vulnerability-in-store-files https://github.com/NousResearch/hermes-agent/pull/30917

Frequently Asked Questions

What is CVE-2026-53870? +

Hermes Agent before 0.16.0 creates response_store.db and webhook_subscriptions.json with world-readable permissions (mode 0o644), exposing conversation history and HMAC secrets to local users. Attackers with local filesystem access can read these files directly to obtain sensitive data including conversation history, tool payloads, prompts, and per-route HMAC secrets. It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2026-53870? +

CVE-2026-53870 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0011, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-53870? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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