{"id":"CVE-2021-31439","url":"https://www.cyber-defence.io/tools/cve/CVE-2021-31439","generatedAt":"2026-10-27T22:23:41.122Z","title":"This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of Synology DiskStation Manager.","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.","published":"2021-05-21T15:15:08.000Z","lastModified":"2026-06-17T03:51:47.000Z","status":"Modified","sourceIdentifier":"zdi-disclosures@trendmicro.com","cvss":{"version":"3.1","score":8.8,"severity":"HIGH","vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"},"cwe":["CWE-122","CWE-787"],"affected":["synology/diskstation manager","debian/debian linux","netatalk/netatalk"],"epss":{"score":0.02331,"percentile":0.83421,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (2.33%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://lists.debian.org/debian-lts-announce/2023/05/msg00018.html","tags":["Mailing List","Third Party Advisory"],"source":"zdi-disclosures@trendmicro.com"},{"url":"https://security.gentoo.org/glsa/202311-02","tags":["Issue Tracking","Third Party Advisory"],"source":"zdi-disclosures@trendmicro.com"},{"url":"https://www.debian.org/security/2023/dsa-5503","tags":["Third Party Advisory"],"source":"zdi-disclosures@trendmicro.com"},{"url":"https://www.synology.com/zh-hk/security/advisory/Synology_SA_20_26","tags":["Vendor Advisory"],"source":"zdi-disclosures@trendmicro.com"},{"url":"https://www.zerodayinitiative.com/advisories/ZDI-21-492/","tags":["Third Party Advisory","VDB Entry"],"source":"zdi-disclosures@trendmicro.com"},{"url":"https://lists.debian.org/debian-lts-announce/2023/05/msg00018.html","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.gentoo.org/glsa/202311-02","tags":["Issue Tracking","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.debian.org/security/2023/dsa-5503","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.synology.com/zh-hk/security/advisory/Synology_SA_20_26","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.zerodayinitiative.com/advisories/ZDI-21-492/","tags":["Third Party Advisory","VDB Entry"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-31439","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}