CVE-2026-69702 Overview
CVE-2026-69702 is a denial of service vulnerability in SnailJob 1.7.0. The flaw resides in the FuryUtil.deserialize helper, which fails to validate the declared decompressed size in Zstandard frame headers. Authenticated attackers can submit a base64-encoded Zstandard payload with an inflated frame_content_size field inside a retry task argument. When the retry-task pipeline dispatches the task, the Java Virtual Machine (JVM) attempts an unbounded array allocation and throws an unrecoverable java.lang.OutOfMemoryError, crashing the server. The weakness is classified as [CWE-789: Memory Allocation with Excessive Size Value].
Critical Impact
Authenticated attackers can crash the SnailJob server with a single crafted retry task payload, resulting in loss of scheduled job execution across dependent services.
Affected Products
- SnailJob 1.7.0
- Aizuda SnailJob distributed retry and scheduling platform (versions prior to 2.0.0)
- Deployments consuming retry task arguments through the FuryUtil.deserialize code path
Discovery Timeline
- 2026-08-04 - CVE-2026-69702 published to the National Vulnerability Database (NVD)
- 2026-08-05 - Last updated in NVD database
Technical Details for CVE-2026-69702
Vulnerability Analysis
SnailJob uses the Fury serialization library to encode and decode retry task arguments transported through its scheduling pipeline. The FuryUtil.deserialize helper transparently decompresses payloads compressed with Zstandard before hydrating them into Java objects. The helper trusts the frame_content_size field in the Zstandard frame header and preallocates a byte buffer sized to that value. An attacker who can submit retry tasks can embed a base64-encoded payload whose header declares a decompressed length in the gigabyte range while the compressed body remains only a few bytes. When the dispatcher processes the task, the JVM requests an oversized array and terminates with java.lang.OutOfMemoryError, taking down the scheduler process.
Root Cause
The root cause is missing validation of externally supplied size fields before allocation. FuryUtil.deserialize reads the untrusted frame_content_size value from the Zstandard header and passes it directly to the buffer allocator. No upper bound, quota, or streaming decompression mode is enforced, matching the pattern described by [CWE-789].
Attack Vector
Exploitation requires network access to the SnailJob API and low-privilege authenticated credentials capable of creating or updating a retry task. The attacker stores a base64-encoded Zstandard blob in a task argument field. Delivery is asynchronous: the payload triggers the fault only when the retry-task pipeline deserializes the argument. No user interaction is required, and a single message is sufficient to abort the JVM.
No verified proof-of-concept code is publicly available. See the VulnCheck Denial of Service Advisory and the Gitee Issue Discussion for the vendor's technical description.
Detection Methods for CVE-2026-69702
Indicators of Compromise
- Repeated java.lang.OutOfMemoryError entries in SnailJob server logs shortly after retry task dispatch.
- Unexpected JVM restarts or heap dump generation correlated with retry-task queue activity.
- Retry task arguments containing base64-encoded values that decode to the Zstandard magic number 0x28B52FFD.
Detection Strategies
- Inspect retry task arguments at ingestion for Zstandard-framed payloads and reject frames whose declared frame_content_size exceeds a safe threshold.
- Correlate authenticated SnailJob API calls that create or update retry tasks with subsequent scheduler crashes in the same time window.
- Monitor for anomalous ratios between compressed payload size and declared decompressed size across retry task submissions.
Monitoring Recommendations
- Alert on JVM heap usage spikes and OutOfMemoryError exceptions in SnailJob server processes.
- Track authentication events and audit which accounts submit retry tasks containing binary or base64-encoded arguments.
- Ship SnailJob application logs and JVM garbage collection metrics to a central data lake for retention and cross-service correlation.
How to Mitigate CVE-2026-69702
Immediate Actions Required
- Upgrade SnailJob to release 2.0.0 or later, which addresses the unbounded allocation in FuryUtil.deserialize.
- Rotate and audit credentials that hold retry task creation privileges until the upgrade is verified in production.
- Restrict network exposure of the SnailJob management API to trusted administrative networks only.
Patch Information
The vendor released a fixed build in the v2.0.0 series. Refer to the Gitee Release Notes and the Gitee Project Repository for the corrected FuryUtil implementation and upgrade instructions.
Workarounds
- Enforce strict role-based access control so that only trusted operators can create or edit retry tasks.
- Apply a JVM heap ceiling (-Xmx) sized to fail fast and add a supervisor that restarts the process on OutOfMemoryError to reduce outage duration.
- Add an application-layer filter that rejects retry task arguments containing the Zstandard magic bytes until the patched release is deployed.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
