How severe is CVE-2026-29045?

CVE-2026-29045 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2026-29045 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (35th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-29045?

CVE-2026-29045 affects Hono. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-29045?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-29045 have an EU (EUVD) identifier?

Yes. CVE-2026-29045 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-9506.

When was CVE-2026-29045 published?

CVE-2026-29045 was published on 2026-03-04 and last updated on 2026-06-17.

CVE-2026-29045

CVE-2026-29045 is a high-severity vulnerability in Hono with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-177.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 0% (35th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-9506
Weakness: CWE-177
Affected product: Hono
Published: 2026-03-04
Last modified: 2026-06-17

Description

Hono is a Web application framework that provides support for any JavaScript runtime. Prior to version 4.12.4, when using serveStatic together with route-based middleware protections (e.g. app.use('/admin/*', ...)), inconsistent URL decoding allowed protected static resources to be accessed without authorization. The router used decodeURI, while serveStatic used decodeURIComponent. This mismatch allowed paths containing encoded slashes (%2F) to bypass middleware protections while still resolving to the intended filesystem path. This issue has been patched in version 4.12.4.

Frequently asked questions

What is CVE-2026-29045?: Hono is a Web application framework that provides support for any JavaScript runtime. Prior to version 4.12.4, when using serveStatic together with route-based middleware protections (e.g. app.use('/admin/*', ...)), inconsistent URL decoding allowed protected static resources to be accessed without authorization. The router used decodeURI, while serveStatic used decodeURIComponent. This mismatch allowed paths containing encoded slashes (%2F) to bypass middleware protections while still resolving to the intended filesystem path. This issue has been patched in version 4.12.4.
How severe is CVE-2026-29045?: CVE-2026-29045 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2026-29045 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (35th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-29045?: CVE-2026-29045 affects Hono. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-29045?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-29045 have an EU (EUVD) identifier?: Yes. CVE-2026-29045 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-9506.
When was CVE-2026-29045 published?: CVE-2026-29045 was published on 2026-03-04 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:hono:hono:*:*:*:*:*:node.js:*:*

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