CVE-2026-57527 json
ZAP ViewState Add-on Insecure Deserialization via JSFViewState.decode()
published 2026-06-26 4 mo ago modified 2026-11-08 27 h ago also EUVD-2026-39777
- cvss
- 8.8
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.7%
- EPSS 0.7% chance of exploitation in 30 days, percentile 52%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- zaproxy zap-extensions 4
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- total
- Assessed
- 4 mo ago
Exploit prediction
0.68% chance of exploitation in the next 30 days, higher than 52% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 8.7 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N |
| CNA | 3.1 | 8.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H |
| CNA | 4.0 | 8.7 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
Affected products
- zaproxy zap-extensions
Classification
- Weakness
-
- CWE-502 Deserialization of Untrusted Data
References
-
github.com
/zaproxy/zap-extensions/pull/7481
issue-tracking, patch
-
github.com
/zaproxy/zap-extensions/commit/ac6c3f94d38505bc0facea286a4d3728044c6e5c
patch
-
zaproxy.org
/blog/2026-06-24-java-deserialization-vulnerability-in-zap-viewstate-addon/
technical-description, vendor-advisory
-
github.com
/zaproxy/zap-extensions/releases/tag/viewstate-v4
release-notes
-
vulncheck.com
/advisories/zap-viewstate-add-on-insecure-deserialization-via-jsfviewstate-decode
third-party-advisory
Sources
- CVE List CVE-2026-57527
- NVD CVE-2026-57527
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