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🛡️ Sentinel: [CRITICAL] Fix insecure deserialization #97

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🛡️ Sentinel: [CRITICAL] Fix insecure deserialization #97

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0e703c6
🛡️ Sentinel: [CRITICAL] Fix insecure deserialization
google-labs-jules[bot] Jun 27, 2026
30af267
🛡️ Sentinel: [CRITICAL] Fix insecure deserialization
google-labs-jules[bot] Jun 27, 2026
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4 changes: 4 additions & 0 deletions .jules/sentinel.md
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Original file line number Diff line number Diff line change
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## 2026-06-27 - [Insecure Deserialization in Utils.readSerializable]
**Vulnerability:** In `me.desair.tus.server.util.Utils.readSerializable`, the code previously used an unrestricted `ObjectInputStream` to deserialize objects from a file on disk. This is a potential risk for arbitrary code execution if an attacker is able to upload a maliciously crafted serialized object and have it processed by the server, as the internal state objects (like `UploadInfo`) are serialized and deserialized to disk.
**Learning:** Java object deserialization is inherently insecure when deserializing untrusted data. Using an unrestricted `ObjectInputStream` opens the application to a wide range of deserialization attacks, even if the stream source is a local file, if that file can be influenced by an attacker (e.g., via a file upload vulnerability).
**Prevention:** Always use `org.apache.commons.io.serialization.ValidatingObjectInputStream` (or implement a custom `ObjectInputStream` that overrides `resolveClass`) to explicitly allow-list accepted classes or packages. The allow-list should be as narrow as possible (e.g., `java.lang.*`, `java.util.*`, and specific application packages).
6 changes: 4 additions & 2 deletions src/main/java/me/desair/tus/server/util/Utils.java
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Expand Up @@ -8,7 +8,6 @@
import jakarta.servlet.http.HttpServletRequest;
import java.io.BufferedOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutput;
import java.io.ObjectOutputStream;
import java.io.OutputStream;
Expand All @@ -22,6 +21,7 @@
import java.util.regex.Pattern;
import me.desair.tus.server.HttpHeader;
import me.desair.tus.server.checksum.ChecksumAlgorithm;
import org.apache.commons.io.serialization.ValidatingObjectInputStream;
import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
Expand Down Expand Up @@ -83,7 +83,9 @@ public static <T> T readSerializable(Path path, Class<T> clazz) throws IOExcepti
// Lock will be released when the channel is closed
if (lockFileShared(channel) != null) {

try (ObjectInputStream ois = new ObjectInputStream(Channels.newInputStream(channel))) {
try (ValidatingObjectInputStream ois =
new ValidatingObjectInputStream(Channels.newInputStream(channel))) {
ois.accept("java.lang.*", "java.util.*", "me.desair.tus.server.*");
info = clazz.cast(ois.readObject());
} catch (ClassNotFoundException
| java.io.EOFException
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