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

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.

Scores

EPSS (exploitation in 30 days)

0.20% · top 90% of all CVEs (6 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: no · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 4.3.

Weakness

• CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection') (opens in a new tab)All about CWE-74 and its CVEs
• CWE-116: Improper Encoding or Escaping of Output (opens in a new tab)All about CWE-116 and its CVEs

Affected products

• honojs · hono

  • affected < 4.12.18

Affected packages

From reviewed advisories of the GitHub Advisory Database.

• npmhonoGHSA-qp7p-654g-cw7p (opens in a new tab)

References (1)

• https://github.com/honojs/hono/security/advisories/GHSA-qp7p-654g-cw7p (opens in a new tab)x_refsource_CONFIRM

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisory GHSA-qp7p-654g-cw7p (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2026-44458](https://trackcve.app/badge/CVE-2026-44458.svg)](https://trackcve.app/cve/CVE-2026-44458)

Record last updated 14 May 2026, 16:00 UTC.