CVE-2026-44458

Hono: CSS Declaration Injection via Style Object Values in JSX SSR

MEDIUM
4.3
CVSS Score
Published: May 13, 2026 at 03:01 PM UTC
Updated: October 26, 2026 at 02:10 PM UTC
2 products affected across 2 vendorsHonoHono

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Severity
MEDIUM4.3
Exploit prediction
EPSS 0.2%
SSVC
No known exploit

Description

Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.12.18, the JSX renderer escapes style attribute object values for HTML but not for CSS. Untrusted input in a style object value or property name can therefore inject additional CSS declarations into the rendered style attribute. The impact is limited to CSS and does not allow JavaScript execution or HTML attribute breakout. This vulnerability is fixed in 4.12.18.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 4.12.18
v < 4.12.18
Affected range stops below 4.12.18, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (1)

x_refsource_CONFIRMVendor Advisory
Source: cverecord
https://github.com/honojs/hono/security/advisories/GHSA-qp7p-654g-cw7p

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

4.3MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
NONE
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-74CWE-116

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