CVE-2021-21404— Crash due to malformed relay protocol message
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I. Basic Information for CVE-2021-21404
Vulnerability Information
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Vulnerability Title
Crash due to malformed relay protocol message
Source: NVD (National Vulnerability Database)
Vulnerability Description
Syncthing is a continuous file synchronization program. In Syncthing before version 1.15.0, the relay server `strelaysrv` can be caused to crash and exit by sending a relay message with a negative length field. Similarly, Syncthing itself can crash for the same reason if given a malformed message from a malicious relay server when attempting to join the relay. Relay joins are essentially random (from a subset of low latency relays) and Syncthing will by default restart when crashing, at which point it's likely to pick another non-malicious relay. This flaw is fixed in version 1.15.0.
Source: NVD (National Vulnerability Database)
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: NVD (National Vulnerability Database)
Vulnerability Type
输入验证不恰当
Source: NVD (National Vulnerability Database)
Vulnerability Title
Jakob Borg syncthing 输入验证错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Jakob Borg syncthing是Jakob Borg开源的一个应用软件。一个连续的文件同步程序。 Syncthing before version 1.15.0 存在安全漏洞，该漏洞源于可能会因发送带有负长度字段的中继消息而崩溃并退出。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Affected Products
II. Public POCs for CVE-2021-21404
| # | POC Description | Source Link | Shenlong Link |
|---|
AI-Generated POCPremium
Qwen3.6-35B-A3B · 7758 chars
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III. Intelligence Information for CVE-2021-21404
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- https://github.com/syncthing/syncthing/releases/tag/v1.15.0x_refsource_MISC
- https://pkg.go.dev/github.com/syncthing/syncthingx_refsource_MISC
- https://nvd.nist.gov/vuln/detail/CVE-2021-21404
IV. Related Vulnerabilities
Same weakness: CWE-20
V. Comments for CVE-2021-21404
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