Security Digest · Vulnerability record
CVE-2023-49093: HtmlUnit vulnerable to Remote Code Execution (RCE) via XSTL
HtmlUnit is a GUI-less browser for Java programs.
CVSS 9.8 Critical EPSS 2.4% · p84
Should you act?
Critical and remotely reachable
No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 2.4%, percentile 84: FIRST’s model estimates a 2.4% chance of exploitation activity in the next 30 days, higher than 84% of all scored CVEs (elevated). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes
org.htmlunit:htmlunit(Maven) < 3.9.0, fixed in 3.9.0. Check your lockfile, including transitive dependencies.
What it is
HtmlUnit is a GUI-less browser for Java programs. HtmlUnit is vulnerable to Remote Code Execution (RCE) via XSTL, when browsing the attacker’s webpage. This vulnerability has been patched in version 3.9.0
From the GitHub advisory
Summary HtmlUnit 3.8.0 are vulnerable to Remote Code Execution (RCE) via XSTL, when browsing the attacker’s webpage
Details Vulnerability code location: org.htmlunit.activex.javascript.msxml.XSLProcessor#transform(org.htmlunit.activex.javascript.msxml.XMLDOMNode)
The reason for the vulnerability is that it was not enabled FEATURESECUREPROCESSING for the XSLT processor
PoC pom.xml:
code:
Weakness type: CWE-94.
Product: org.htmlunit:htmlunit (Maven) · Assigned by: GitHub_M · Published: 2023-12-04
Affected and fixed versions
| Ecosystem | Package | Vulnerable | First fixed |
|---|---|---|---|
| Maven | org.htmlunit:htmlunit | < 3.9.0 | 3.9.0 |
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| HtmlUnit | htmlunit | < 3.9.0 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_M | 3.1 | 9.8 Critical | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| GitHub | 3.1 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Privileges required: none (no login)
- User interaction: none
- Scope: unchanged
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc, automatable yes, technical impact total.
- FIRST EPSS (model of 2026-10-21): 2.36% probability of exploitation activity in the next 30 days; percentile 84.
Timeline
- — CVE record published by GitHub_M
- — GitHub-reviewed advisory GHSA-37vq-hr2f-g7h7 published (critical)
- — CVE record last updated
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vulnerability records
- GitHub Advisory GHSA-37vq-hr2f-g7h7 github.com
- CVE.org record CVE-2023-49093 cve.org
- NVD entry CVE-2023-49093 nvd.nist.gov
Other references from the CVE record and advisory
- github.com github.com
- htmlunit.org htmlunit.org