Is CVE-2026-59897 in the CISA KEV catalog?

No. CVE-2026-59897 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-59897?

CVE-2026-59897 has a CVSS v3 base score of 4.8 (MEDIUM).

What is the EPSS score for CVE-2026-59897?

CVE-2026-59897 has an EPSS score of 0.13% (3th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-59897?

Upgrade hono to 4.12.27 or later.

CVE & CISA-KEV Catalog

CVE-2026-59897

MEDIUM

4.8

CVSS v3

NVD

Description

Hono is a Web application framework that provides support for any JavaScript runtime. From 4.3.3 before 4.12.27, the AWS API Gateway v1 adapter can drop a distinct repeated request header value because it de-duplicates values using a substring comparison instead of an exact match, so middleware or application logic that depends on the complete X-Forwarded-For chain, rate limiting, audit logging, or proxy-chain validation can receive incomplete data. This issue is fixed in version 4.12.27.

CWE-348

How to fix

Remediation Available

honoNVD

Affected:>= 4.3.3, < 4.12.27Fixed in:4.12.27CVE-2026-59897derived from NVD

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityHigh

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityLow

IntegrityLow

AvailabilityNone

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

Exploit Intelligence

0.13%probability of exploitation in 30 days

3rdpercentile

Low risk: more likely to be exploited than 3% of all known CVEs.

References

Patch1

github.com

Vendor Advisory1

github.com

Release Notes1

github.com

Related Vulnerabilities

Other CWE-348 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2025-59951	Critical	9.1	4.7%	-	-
CVE-2022-31813	Critical	9.8	3.1%	-	Fix
CVE-2024-45410	Critical	9.8	1.5%	-	Fix
CVE-2021-21373	High	7.5	1.2%	-	Fix
CVE-2021-21374	High	8.1	1.0%	-	Fix
CVE-2022-2255	High	7.5	0.7%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-07-10.