Correct historical context of deserialization FAQ - #43
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The security FAQ claimed that the `SocketServer` receiver was never reintroduced into the Log4j 2 production codebase. This is inaccurate: `log4j-core` contained TCP and UDP socket servers inherited from Log4j 1 up to and including the 2.8.x releases. As any endpoint consuming serialized data, they were dangerous to use and resulted in CVE-2017-5645. The vulnerability was patched in 2.8.2 by introducing `FilteredObjectInputStream` as a Java 7 equivalent of the `ObjectInputFilter` API introduced in Java 9, but since the fix could not cover all cases the socket servers were removed in 2.9.0. This change corrects the section and expands it with this history, cross-linking the CVE-2017-5645 entry on the security page. Assisted-By: Claude Fable 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01GeV6uBXR77uZVnPAUUjF6n
ppkarwasz
enabled auto-merge (squash)
August 27, 2026 05:09
FreeAndNil
approved these changes
Aug 27, 2026
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The security FAQ claimed that the
SocketServerreceiver was never reintroduced into the Log4j 2 production codebase. This is inaccurate:log4j-corecontained TCP and UDP socket servers inherited from Log4j 1 up to and including the 2.8.x releases. As any endpoint consuming serialized data, they were dangerous to use and resulted in CVE-2017-5645. The vulnerability was patched in 2.8.2 by introducingFilteredObjectInputStreamas a Java 7 equivalent of theObjectInputFilterAPI introduced in Java 9, but since the fix could not cover all cases the socket servers were removed in 2.9.0.This change corrects the section and expands it with this history, cross-linking the CVE-2017-5645 entry on the security page.
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https://claude.ai/code/session_01GeV6uBXR77uZVnPAUUjF6n