How severe is CVE-2026-56764?

No CVSS score has been assigned to CVE-2026-56764 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-56764?

CVE-2026-56764 affects the following packages: hono (npm). Ecosystems affected: npm.

How do I fix CVE-2026-56764?

Update hono to 4.11.10 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-56764 is resolved across your whole dependency graph.

How do I detect CVE-2026-56764 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for hono, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-56764 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2026-56764 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-56764 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-56764?

CVE-2026-56764 has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 22th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-56764?

CVE-2026-56764 is classified as CWE-208 (CWE-208). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-56764 published, and has it been updated?

CVE-2026-56764 was published on July 15, 2026 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦 npm

Not in CISA KEV

CVE-2026-56764 — hono

Fix: honojs/hono@91def7c

CVE-2026-56764 is a CWE-208 vulnerability in hono. A fix is available for hono — see the affected versions and patch details below.

Hono - Timing Attack in basicAuth and bearerAuth Middleware

Also known asGHSA-gq3j-xvxp-8hrf

Published

Jul 15, 2026

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 7, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-56764.

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs22th percentile — riskier than 22% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

7Kother npm packages depend on this — each one inherits the vulnerability until it's patched upstream

hononpm

104.0Mdownloads / week

Description

Summary

The basicAuth and bearerAuth middlewares previously used a comparison that was not fully timing-safe.

The timingSafeEqual function used normal string equality (===) when comparing hash values. This comparison may stop early if values differ, which can theoretically cause small timing differences.

The implementation has been updated to use a safer comparison method.

Details

The issue was caused by the use of normal string equality (===) when comparing hash values inside the timingSafeEqual function.

In JavaScript, string comparison may stop as soon as a difference is found. This means the comparison time can slightly vary depending on how many characters match.

Under very specific and controlled conditions, this behavior could theoretically allow timing-based analysis.

The implementation has been updated to:

Avoid early termination during comparison
Use a constant-time-style comparison method

Impact

This issue is unlikely to be exploited in normal environments.

It may only be relevant in highly controlled situations where precise timing measurements are possible.

This change is considered a security hardening improvement. Users are encouraged to upgrade to the latest version.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`hono`	all versions	4.11.10`npm install hono@4.11.10`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for hono, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update hono to 4.11.10 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-56764 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatLow

Product	Fixed in	Advisory
Red Hat Hardened Images	`grafana13-1-main-13.1.1-0.2.hum1`	RHSA-2026:47618
Red Hat Hardened Images	`grafana12-4-main-12.4.6-0.2.hum1`	RHSA-2026:47619

Frequently Asked Questions

## Summary The `basicAuth` and `bearerAuth` middlewares previously used a comparison that was not fully timing-safe. The `timingSafeEqual` function used normal string equality (`===`) when comparing hash values. This comparison may stop early if values differ, which can theoretically cause small timing differences. The implementation has been updated to use a safer comparison method. ## Details The issue was caused by the use of normal string equality (`===`) when comparing hash values inside the `timingSafeEqual` function. In JavaScript, string comparison may stop as soon as a differen

O3 Security · Impact-Aware SCA

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