Security Resilience

CVE-2025-27109

XSS

XSS
Published
21 February 2025
Modified
15 April 2026
CVSS Score v3.1 7.3
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
EPSS Score 0.0033 25th percentile
Risk Priority 55 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2025-27109 is a high-severity Cross-site Scripting (CWE-79) vulnerability. Its CVSS base score is 7.3 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Browser Session Hijacking (T1185); ranked at the 25th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2025-27109 affects solid-js, a declarative JavaScript library for building user interfaces, in versions prior to 1.9.4. The vulnerability arises when inserts/JSX expressions inside illegal inlined JSX fragments lack proper escaping, allowing user input placed directly inside those fragments to be rendered as HTML. This flaw is classified under CWE-79 (cross-site scripting) and CWE-116 (improper encoding or escaping of output).

The vulnerability carries a CVSS v3.1 base score of 7.3 (AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L), indicating it is exploitable remotely over the network by unauthenticated attackers with low complexity and no user interaction required. Attackers can achieve limited impacts on confidentiality, integrity, and availability by injecting user-controlled data into affected JSX fragments, resulting in the execution of arbitrary HTML in the victim's browser context.

The SolidJS security advisory (GHSA-3qxh-p7jc-5xh6) and fixing commit (b93956f28ed75469af6976a98728e313d0edd236) confirm the issue was addressed in version 1.9.4, urging all users to upgrade immediately. No workarounds are known.

OWASP Top 10 for Web (2025)

A05:2025 Injection

EU & UK References

Vulnerability Data

solid-js is a declarative, efficient, and flexible JavaScript library for building user interfaces. In affected versions Inserts/JSX expressions inside illegal inlined JSX fragments lacked escaping, allowing user input to be rendered as HTML when put directly inside JSX fragments. This…

more

issue has been addressed in version 1.9.4 and all users are advised to upgrade. There are no known workarounds for this vulnerability.

CWE(s)
CWE-79CWE-116

Related Threats

MITRE ATT&CK Enterprise Techniques

T1185 Browser Session Hijacking Collection
Adversaries may take advantage of security vulnerabilities and inherent functionality in browser software to change content, modify user-behaviors, and intercept information as part of various browser session hijacking techniques.
attack.mitre.org →
T1539 Steal Web Session Cookie Credential Access
An adversary may steal web application or service session cookies and use them to gain access to web applications or Internet services as an authenticated user without needing credentials.
attack.mitre.org →
T1189 Drive-by Compromise Initial Access
Adversaries may gain access to a system through a user visiting a website over the normal course of browsing.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1204.001 Malicious Link Execution
An adversary may rely upon a user clicking a malicious link in order to gain execution.
attack.mitre.org →
T1491.002 External Defacement Impact
An adversary may deface systems external to an organization in an attempt to deliver messaging, intimidate, or otherwise mislead an organization or users.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-37875Shared CWE-116, CWE-79
CVE-2026-40593Shared CWE-116, CWE-79
CVE-2026-23630Shared CWE-116, CWE-79
CVE-2025-48007Shared CWE-116, CWE-79
CVE-2026-26028Shared CWE-116, CWE-79
CVE-2026-107845Shared CWE-116, CWE-79
CVE-2026-41426Shared CWE-116, CWE-79
CVE-2026-35569Shared CWE-116, CWE-79
CVE-2026-59895Shared CWE-116, CWE-79
CVE-2025-64325Shared CWE-116, CWE-79

Affected Assets

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V1.1.2
  • V1.3.2

Mitigating Controls (NIST 800-53 r5) AI

SA-11 Developer Testing and Evaluation good match

Developer testing and evaluation can discover missing or incorrect input neutralization through targeted web-application tests.

SI-10 Information Input Validation good match

Input validation directly enforces neutralization of untrusted data before it reaches web output generation.

SI-15 Information Output Filtering good match

Output filtering can catch or sanitize unneutralized script content before it is served to users.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
blocks

Secure SDLC practices directly target introduction of XSS via coding standards/testing (mostly), yet the single broad outcome leaves many specific neutralization vectors unaddressed (partial).

PR.PS-02 partial match
blocks

Patching and EOL replacement can remediate known XSS instances in libraries or frameworks (partial) but do nothing to enforce input neutralization in application code (none).

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance mostly match
finds

Secure-coding testing and automated code-analysis tools are applied to detect improper neutralization of script-related content during web-page generation.

A.8.28 Secure coding partial match
prevents

Secure-coding standards, SAST scans and removal of insecure code samples together eliminate the failure to neutralize script content that produces cross-site scripting flaws.

Hardening callouts derived

DISA STIG baselines are authored against specific weaknesses. Where this CVE cites a broad weakness class, the mapping is not asserted at that abstraction (owner ruling, 2026-09-25: grade only at Base and below), so no rule is shown here rather than a rule shown against the wrong grain.

  • No fine-grained STIG row for CWE-116, a class-level weakness, and none of its children carries one either.

References