HTML injection via unvalidated JSX tag names
Published May 13, 2026 · Updated May 13, 2026
HTML injection in hono/jsx before 4.12.16 allows remote attackers to alter server-rendered output through untrusted JSX tag names. The JSX renderer inserts programmatic jsx() or createElement() tag names into HTML strings without validating angle brackets, quotes, or whitespace. Reachability requires an application to derive a tag name from attacker-controlled data; static or allowlisted names are unaffected, while successful injection can add elements, attributes, or event handlers.
Summary
What happened
HTML injection in hono/jsx before 4.12.16 allows remote attackers to alter server-rendered output through untrusted JSX tag names. The JSX renderer inserts programmatic jsx() or createElement() tag names into HTML strings without validating angle brackets, quotes, or whitespace. Reachability requires an application to derive a tag name from attacker-controlled data; static or allowlisted names are unaffected, while successful injection can add elements, attributes, or event handlers.
The record
- CVE
- CVE-2026-44455
- Published
- May 13, 2026
- Updated
- May 13, 2026
- Vendor
- Hono
- Product
- Hono
- Classifications
- CWE-74, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- May 13, 2026CVE publishedPublication date reported by the CVE source.
- May 13, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 4.12.16
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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