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Fencer Vulns
high 8.8

CVE-2021-31439 json

This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of Synology DiskStation Manager.

published 2021-05-21 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-18339

cvss
8.8
version 3.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
2.3%
EPSS 2.3% chance of exploitation in 30 days, percentile 83%
public exploits
0
none known

Summary

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.

Patch / fix

  • netatalk netatalk 3.1.13
  • synology diskstation_manager 6.2.3-25426-3
  • netatalk Debian 14, Debian 13 3.1.13~ds-1

debian advisories DEBIAN-CVE-2021-31439

  • netatalk Ubuntu 20.04 LTS 3.1.12~ds-4ubuntu0.20.04.1
  • netatalk Ubuntu 22.04 LTS 3.1.12~ds-9ubuntu0.22.04.1

ubuntu advisories UBUNTU-CVE-2021-31439

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • netatalk SLE Workstation Extension 12 SP5, SLE Software Development Kit 12 SP5 3.1.0-3.8.1

suse advisories SUSE-SU-2022:1184-1

  • netatalk Alpine 3.24, Alpine 3.23, Alpine 3.22 +6 more 3.1.13-r0

alpine advisories ALPINE-CVE-2021-31439

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Exploit prediction

2.33% chance of exploitation in the next 30 days, higher than 83% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.0 8.8 CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 3.1 8.8 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 5.8 AV:A/AC:L/Au:N/C:P/I:P/A:P

Affected products

  • Synology DiskStation Manager

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.