Python
CVE-2026-21873
HIGH
GHSA-mhpg-c27v-6mxr
Severity by source
AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
Primary rating from GitHub Advisory · only source for this CVE.
CVSS VectorGitHub Advisory
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
Lifecycle Timeline
4DescriptionGitHub Advisory
NiceGUI is a Python-based UI framework. From versions 2.22.0 to 3.4.1, an unsafe implementation in the pushstate event listener used by ui.sub_pages allows an attacker to manipulate the fragment identifier of the URL, which they can do despite being cross-site, using an iframe. This issue has been patched in version 3.5.0.
AnalysisAI
NiceGUI versions 2.22.0 through 3.4.1 contain a cross-site DOM-based XSS vulnerability in the pushstate event listener for ui.sub_pages that allows attackers to manipulate URL fragment identifiers via iframe injection. Public exploit code exists for this vulnerability, and affected users should upgrade to version 3.5.0 or later as no patch is currently available for vulnerable versions.
Unlock full vulnerability intelligence
- Risk assessment & exploitation conditions
- Attack chain visualization
- Remediation with exact patch versions
- Threat intelligence from 22 sources
- Personal watchlist & email alerts
Free forever · No credit card required
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | NiceGUI versions 2.22.0 to 3.4.1 with ui.sub_pages feature enabled; application rendered in iframe context allowing cross-site fragment manipulation; no authentication required. Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | CVSS 7.2 (HIGH). … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker could exploit this vulnerability to manipulate the fragment identifier of the URL, which they can do despite being c. |
| Remediation | Fixed in version 3.5.0.. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 7 days: Identify all affected systems and apply vendor patches promptly. …
Sign in for detailed remediation steps and compensating controls.
Threat intelligence, references, and detailed analysis are available after sign-in.
More from same product – last 7 days
Unauthenticated remote attackers can invoke MCP tool handlers and exfiltrate the operator's long-lived Meta Graph API ac
Unauthenticated remote code execution in Crawl4AI versions <= 0.8.6 allows attackers to escape the AST-based sandbox in
Remote code execution in Langflow versions through 1.9.1 allows unauthenticated attackers to execute arbitrary Python co
Authenticated remote code execution in ChromaDB Python project versions 0.4.17 and later enables attackers holding the U
Remote code execution in python-statemachine 3.0.0 through 3.1.x allows attackers to run arbitrary Python in the host pr
Share
External POC / Exploit Code
Leaving vuln.today