CVE-2021-31439: This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of Synology DiskStation Manager.
Noroxi assessment
Priority: Monitor (action score 36/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 2.3% (FIRST EPSS); higher than 83.7% of all records.
- Someone on the same network segment can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
- Fixed version: netatalk (Alpine:v3.16) 3.1.13-r0; netatalk (Debian:10) 3.1.12~ds-3+deb10u1; netatalk (Debian:11) 3.1.12~ds-8+deb11u1.
- Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).
Low priority for now. Upgrade to netatalk (Alpine:v3.16) 3.1.13-r0; netatalk (Debian:10) 3.1.12~ds-3+deb10u1; netatalk (Debian:11) 3.1.12~ds-8+deb11u1 or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
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
- May 21, 2021
- Updated
- Jun 16, 2026
- EPSS
- 2.3% · 83th percentile
- CWE
- CWE-122
Report tools
Action score
36
Low priority for now.
- CVSS
- 35 / 40 · 8.8 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 1 / 30 · 2.3%
CNA vs NVD score
- NVD
- 8.8
- CNA · zdi
- 8.8
- agree
CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
Is your version affected? Check itNoroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| Vendor | Product | CPE |
|---|---|---|
| synology | diskstation manager | cpe:2.3:o:synology:diskstation_manager |
| debian | debian linux | cpe:2.3:o:debian:debian_linux |
| netatalk | netatalk | cpe:2.3:a:netatalk:netatalk |
Versions reported by the vendor
Affected version ranges reported by the assigning authority (zdi). Independent of NVD's CPE analysis and usually ahead of it.
Synology DiskStation Manager
- 6.1.1-15101-4affected
Affected versions · NVD (4)
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- debian debian linux10.0
- debian debian linux11.0
- netatalk netatalkbefore 3.1.13
- synology diskstation manager6.2 and later · before 6.2.3-25426-3
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Alpine:v3.16 | netatalk | before 3.1.13-r0 | 3.1.13-r0 |
| Debian:10 | netatalk | before 3.1.12~ds-3+deb10u1 | 3.1.12~ds-3+deb10u1 |
| Debian:11 | netatalk | before 3.1.12~ds-8+deb11u1 | 3.1.12~ds-8+deb11u1 |
| Debian:13 | netatalk | before 3.1.13~ds-1 | 3.1.13~ds-1 |
| SUSE:Linux Enterprise Software Development Kit 12 SP5 | netatalk | before 3.1.0-3.8.1 | 3.1.0-3.8.1 |
Same product
synology: all recordsOther highest-scoring records for the same primary product.
- CVE-2013-6955webman/imageSelector.cgi in Synology DiskStation Manager (DSM) 4.0 before 4.0-2259, 4.2 before 4.2-3243, and 4.3 before 4.3-3810 Update 1…65This week
- CVE-2017-9554An information exposure vulnerability in forget_passwd.cgi in Synology DiskStation Manager (DSM) before 6.1.3-15152 allows remote attackers…60This week
- CVE-2017-15889Command injection vulnerability in smart.cgi in Synology DiskStation Manager (DSM) before 5.2-5967-5 allows remote authenticated users to…57Plan
Published before and after this one in the same product
- ← EarlierCVE-2021-27647Mar 12, 2021 · Out-of-bounds Read vulnerability in iscsi_snapshot_comm_core in Synology DiskStation Manager (DSM) before 6.2.3-25426-3 allows remote…40Plan
- ← EarlierCVE-2021-29083Apr 1, 2021 · Improper neutralization of special elements used in an OS command in SYNO.Core.Network.PPPoE in Synology DiskStation Manager (DSM) before 6.29Monitor
- Later →CVE-2021-29088Jun 1, 2021 · Improper limitation of a pathname to a restricted directory ('Path Traversal') in cgi component in Synology DiskStation Manager (DSM)…31Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| alpine:netatalk | 3.1.13-r0 · Alpine:v3.16 | Package registry (OSV) |
| debian:netatalk | 3.1.13~ds-1 · Debian:13 | Package registry (OSV) |
| suse:netatalk | 3.1.0-3.8.1 · SUSE:Linux Enterprise Software Development Kit 12 SP5 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
- Angelboy(@scwuaptx)DEVCORE Research Team
National notice (Türkiye Cybersecurity Directorate / USOM)
Official security notices citing this record; remediation advice is on the agency's page.
- TR-23-0336 · Jun 9, 2023(Linux Kernel Güncellemesi)
Not on record for this CVE: EPSS history · patch commit or PR link · variant or chain candidate · public bounty program.
Technical details
Attack conditions
- Someone on the same network segment can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Adjacent
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-122 · Heap-based Buffer OverflowCVSS vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
ATT&CK techniques
—
Change log (1)
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (4 more)Show less
Vendor advisories and official records. Exploit/PoC links are deliberately left out.