Recently, a security researcher discovered an issue with the fixes for multiple versions of fastjson. Despite these fixes, an attacker could remotely execute code on a server running fastjson via a carefully crafted request. This issue affects fastjson 1.2.47 and earlier and does not require enabling the autotype option.
- Fastjson <= 1.2.47
- Fastjson > 1.2.47
Users are advised to upgrade to 1.2.51 or the latest version 1.2.58.
Fastjson has released version 1.2.58 to fix the preceding vulnerability. Affected users are advised to upgrade as soon as possible.
Alternatively, uses can use WAF to block requests that contain “@type” or encoded forms of “@type”.
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