High 8.8Published Jun 26, 2026

CVE-2026-57527ZAP ViewState Add-on Insecure Deserialization via JSFViewState.decode()

Updated under an hour ago (Oct 28, 2026, 4:20 AM ET)

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It affects zaproxy zap-extensions. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Exploited in the last 30 days

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: 8.8 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Weakness (CWE): CWE-502
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: VulnCheck
NVD analysis: Awaiting Analysis
Record last updated: Jul 14, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

zaproxy zap-extensions zaproxy:zap_extensions (from the name)	before 4	CNA record

References

References

https://www.zaproxy.org/blog/2026-06-24-java-deserialization-vulnerability-in-zap-viewstate-addon/	technical-description, vendor-advisory
https://github.com/zaproxy/zap-extensions/releases/tag/viewstate-v4	release-notes
https://github.com/zaproxy/zap-extensions/pull/7481	issue-tracking
https://github.com/zaproxy/zap-extensions/commit/ac6c3f94d38505bc0facea286a4d3728044c6e5c	patch
https://www.vulncheck.com/advisories/zap-viewstate-add-on-insecure-deserialization-via-jsfviewstate-decode	third-party-advisory

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.