CVE-2026-57527: Deserialization of Untrusted Data in zaproxy zap-extensions
Zed Attack Proxy (ZAP) ViewState add-on before version 4 contains an insecure deserialization vulnerability that allows attackers who control a proxied web server to achieve arbitrary code execution by embedding a malicious serialized Java object in the javax.faces.ViewState HTTP response parameter. The JSFViewState.decode() method base64-decodes the ViewState value and passes it directly to ObjectInputStream.readObject() without a deserialization filter, allowlist, or type restriction, causing the malicious object to be deserialized within the ZAP JVM when the Desktop UI renders the ViewState panel.
AI Analysis
Technical Summary
CVE-2026-57527 is an insecure deserialization vulnerability in the Zed Attack Proxy (ZAP) ViewState add-on prior to version 4. The vulnerability occurs because the JSFViewState.decode() method directly deserializes base64-decoded data from the javax.faces.ViewState HTTP response parameter using ObjectInputStream.readObject() without applying deserialization filters, allowlists, or type restrictions. An attacker who controls a proxied web server can embed a malicious serialized Java object in this parameter, causing arbitrary code execution within the ZAP JVM when the Desktop UI processes the ViewState panel. This vulnerability affects zap-extensions versions before 4 and has a CVSS 4.0 score of 8.7, indicating high severity.
Potential Impact
Successful exploitation allows an attacker controlling a proxied web server to achieve arbitrary code execution within the ZAP JVM. This can lead to full compromise of the ZAP application environment running the vulnerable ViewState add-on. The vulnerability is exploitable without privileges or user interaction beyond the victim using the Desktop UI to render the malicious ViewState panel.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, avoid proxying untrusted web servers that may return malicious ViewState parameters. Monitor vendor channels for updates regarding patches or mitigations for this vulnerability.
CVE-2026-57527: Deserialization of Untrusted Data in zaproxy zap-extensions
Description
Zed Attack Proxy (ZAP) ViewState add-on before version 4 contains an insecure deserialization vulnerability that allows attackers who control a proxied web server to achieve arbitrary code execution by embedding a malicious serialized Java object in the javax.faces.ViewState HTTP response parameter. The JSFViewState.decode() method base64-decodes the ViewState value and passes it directly to ObjectInputStream.readObject() without a deserialization filter, allowlist, or type restriction, causing the malicious object to be deserialized within the ZAP JVM when the Desktop UI renders the ViewState panel.
CVSS v4.0
Score 8.7high
Affected software
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-57527 is an insecure deserialization vulnerability in the Zed Attack Proxy (ZAP) ViewState add-on prior to version 4. The vulnerability occurs because the JSFViewState.decode() method directly deserializes base64-decoded data from the javax.faces.ViewState HTTP response parameter using ObjectInputStream.readObject() without applying deserialization filters, allowlists, or type restrictions. An attacker who controls a proxied web server can embed a malicious serialized Java object in this parameter, causing arbitrary code execution within the ZAP JVM when the Desktop UI processes the ViewState panel. This vulnerability affects zap-extensions versions before 4 and has a CVSS 4.0 score of 8.7, indicating high severity.
Potential Impact
Successful exploitation allows an attacker controlling a proxied web server to achieve arbitrary code execution within the ZAP JVM. This can lead to full compromise of the ZAP application environment running the vulnerable ViewState add-on. The vulnerability is exploitable without privileges or user interaction beyond the victim using the Desktop UI to render the malicious ViewState panel.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, avoid proxying untrusted web servers that may return malicious ViewState parameters. Monitor vendor channels for updates regarding patches or mitigations for this vulnerability.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- VulnCheck
- Date Reserved
- 2026-06-24T15:58:58.538Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a3e95a96e08203f7da55afb
Added to database: 06/26/2026, 15:07:21 UTC
Last enriched: 07/15/2026, 10:19:09 UTC
Last updated: 08/09/2026, 12:41:11 UTC
Views: 80
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