HOMEVULNERABILITIESCVE-2021-31439
HIGH

CVE-2021-31439

CWE-122Published: May 21, 2021· Updated: Jun 17, 2026

8.8
CVSS v3.1

Official Description

This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of Synology DiskStation Manager. Authentication is not required to exploit this vulnerablity. The specific flaw exists within the processing of DSI structures in Netatalk. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a heap-based buffer. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-12326.

NVD Source

Technical Analysis

CVE-2021-31439 requires adjacent network access, limiting remote exploitation but still posing risk in shared or local network environments.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 8.8.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorAdjacent
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected Vendors & Products

Debian1 product(s)
debian linux
netatalk1 product(s)
netatalk
synology1 product(s)
diskstation manager
Source: NVD CPE · 4 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

ADVISORYhttps://lists.debian.org/debian-lts-announce/2023/05/msg00018.html
ADVISORYhttps://security.gentoo.org/glsa/202311-02
ADVISORYhttps://www.debian.org/security/2023/dsa-5503
ADVISORYhttps://www.synology.com/zh-hk/security/advisory/Synology_SA_20_26
ADVISORYhttps://www.zerodayinitiative.com/advisories/ZDI-21-492/
ADVISORYhttps://lists.debian.org/debian-lts-announce/2023/05/msg00018.html
ADVISORYhttps://security.gentoo.org/glsa/202311-02
ADVISORYhttps://www.debian.org/security/2023/dsa-5503
ADVISORYhttps://www.synology.com/zh-hk/security/advisory/Synology_SA_20_26
ADVISORYhttps://www.zerodayinitiative.com/advisories/ZDI-21-492/

All References (10)

→
https://lists.debian.org/debian-lts-announce/2023/05/msg00018.htmlMailing List · Third Party Advisory
→
https://security.gentoo.org/glsa/202311-02Issue Tracking · Third Party Advisory
→
https://www.debian.org/security/2023/dsa-5503Third Party Advisory
→
https://www.synology.com/zh-hk/security/advisory/Synology_SA_20_26Vendor Advisory
→
https://www.zerodayinitiative.com/advisories/ZDI-21-492/Third Party Advisory · VDB Entry
→
https://lists.debian.org/debian-lts-announce/2023/05/msg00018.htmlMailing List · Third Party Advisory
→
https://security.gentoo.org/glsa/202311-02Issue Tracking · Third Party Advisory
→
https://www.debian.org/security/2023/dsa-5503Third Party Advisory
→
https://www.synology.com/zh-hk/security/advisory/Synology_SA_20_26Vendor Advisory
→
https://www.zerodayinitiative.com/advisories/ZDI-21-492/Third Party Advisory · VDB Entry

Quick Facts

CVE IDCVE-2021-31439
CVSS Score8.8 / 10
SeverityHIGH
WeaknessCWE-122
CISA KEVNo
Affected3 vendor(s)
PublishedMay 21, 2021

Related CVEs (CWE-122)

CVE-2022-34819
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CVE-2026-46752
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CVE-2025-23123
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CVE-2021-25387
10.0
CVE-2021-21940
10.0
CVE-2026-44050
9.9

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-31439 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.
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