Cyber Resilience

CVE-2025-67438

XSS in Sync-In Server ≤ 1.9.3

Public PoCXSS
Published
20 February 2026
Modified
25 March 2026
Patch / advisory
CVSS Score v3.1 6.1
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
EPSS Score 0.0027 19th percentile
Risk Priority 35 floored blend · peak EPSS

Summary

CVE-2025-67438 is a medium-severity Cross-site Scripting (CWE-79) vulnerability in Sync-In Sync-In Server. Its CVSS base score is 6.1 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Browser Session Hijacking (T1185); ranked at the 19th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to SI-10 (Information Input Validation) and SI-3 (Malicious Code Protection) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

A Stored Cross-Site Scripting (XSS) vulnerability in Sync-in Server before 1.9.3 allows an authenticated attacker to execute arbitrary JavaScript in a victim's browser. By uploading a crafted SVG file containing a malicious payload, an attacker can access and exfiltrate sensitive…

more

information, including the user's session cookies.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

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.
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.
Why these techniques?

Stored XSS via malicious SVG upload directly enables browser JS execution for session cookie theft/hijacking.

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2023-27293Shared CWE-79
CVE-2023-46003Shared CWE-79
CVE-2023-5343Shared CWE-79
CVE-2023-46650Shared CWE-79
CVE-2023-49272Shared CWE-79
CVE-2023-49271Shared CWE-79
CVE-2023-46659Shared CWE-79
CVE-2023-46287Shared CWE-79
CVE-2023-49490Shared CWE-79
CVE-2023-5894Shared CWE-79

Affected Assets

sync-in
sync-in server
≤ 1.9.3

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)
  • SI-10 Information Input Validation
  • SI-3 Malicious Code Protection
  • SI-15 Information Output Filtering
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

prevent

Directly requires validation and sanitization of all user-supplied input, including uploaded SVG files, to reject or neutralize embedded script payloads before storage.

prevent

Mandates malicious-code scanning and blocking of uploaded content, which would detect and stop the crafted SVG containing executable JavaScript before it is stored and served.

prevent

Requires filtering of information outputs, which can strip or neutralize script content when the stored SVG is later rendered to other users' browsers.

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
prevents

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
prevents

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.

detects

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

prevents

Knowledge exchange on emerging attack techniques and patches reduces the likelihood that cross-site scripting flaws remain unaddressed in deployed applications.

prevents

Operational indicators of compromise for web-application attacks can be incorporated into WAF or input-filtering rules, lowering the likelihood that unsanitized data reaches the browser.

prevents

Requiring language-specific secure-coding standards and automated scanning during the SDLC catches missing output encoding or improper neutralization of untrusted data before the software reaches production.

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.

none

Webpage malware scanning and block-listing of known malicious sites reduce the likelihood that reflected or stored script payloads reach a user’s browser.

References