CVE-2021-31439

HIGHNVD 8.88.8—
EchelonGraph scoreMEDIUM confidence

Score 8.8 from GitHub Security Advisory (severity: HIGH) published 2022-05-24. NVD baseline CVSS 8.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
8.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 2%CVSS: 8.8Exploit: None knownExposed: 0

A fix is available — apply it.

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.

CVSS v3
8.8
EG Score
8.8(medium)
EG Risk
45(Track)
EG Risk 45/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity88% × 45%
Exploitation2% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
2%
EPSS %ILE
83%
KEV
Not listed

Published

May 21, 2021

Last Modified

January 14, 2025

Advisory Details (5)

Auto-updated Aug 24, 2026
Patch available.
generic

ZDI-21-492 - TrendAI™ Zero Day Initiative™ (ZDI)

https://www.zerodayinitiative.com/advisories/ZDI-21-492/
generic

Synology_SA_20_26 | 群暉科技 Synology Inc.

https://www.synology.com/zh-hk/security/advisory/Synology_SA_20_26
generic

[SECURITY] [DSA 5503-1] netatalk security update

https://www.debian.org/security/2023/dsa-5503
generic

Netatalk: Multiple Vulnerabilities including root remote code execution (GLSA 202311-02) — Gentoo security

https://security.gentoo.org/glsa/202311-02
generic Patch Available

[SECURITY] [DLA 3426-1] netatalk security update

https://lists.debian.org/debian-lts-announce/2023/05/msg00018.html

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntunetatalk (2.2.5-1ubuntu0.2+esm1) @ xenial2026-05-26ubuntu

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(4 across 4 ecosystems)
Debian:10(1)
PackageVulnerable rangeFixed inDependents
netatalk3.1.12~ds-33.1.12~ds-3+deb10u1—
Debian:11(1)
PackageVulnerable rangeFixed inDependents
netatalk3.1.12~ds-83.1.12~ds-8+deb11u1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
netatalk—3.1.13~ds-1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
netatalk—3.1.13~ds-1—

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

All Vendor Advisories

(1)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 8× in last 7d / 32× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 164 total refreshes for this CVE.

  1. 2026-09-19 15:37 UTCEPSS rescore
  2. 2026-09-18 19:23 UTCEPSS rescore
  3. 2026-09-17 19:23 UTCEPSS rescore
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  8. 2026-09-13 16:43 UTCEPSS rescore
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  11. 2026-09-11 09:33 UTCEPSS rescore
  12. 2026-09-08 21:56 UTCEPSS rescore
  13. 2026-09-07 15:58 UTCEPSS rescore
  14. 2026-09-06 17:01 UTCOSV refresh
  15. 2026-09-06 13:44 UTCEPSS rescore
  16. 2026-09-05 15:25 UTCEPSS rescore
  17. 2026-09-04 13:57 UTCEPSS rescore
  18. 2026-09-04 05:03 UTCEPSS rescore
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  20. 2026-09-02 14:08 UTCEPSS rescore
  21. 2026-09-01 13:50 UTCEPSS rescore
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  24. 2026-08-30 01:19 UTCEPSS rescore
  25. 2026-08-28 21:37 UTCEPSS rescore
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  1. 2026-08-27 14:22 UTCEPSS rescore
  2. 2026-08-26 14:42 UTCEPSS rescore
  3. 2026-08-25 13:45 UTCEPSS rescore
  4. 2026-08-24 14:12 UTCEPSS rescore
  5. 2026-08-23 00:16 UTCEPSS rescore
  6. 2026-08-21 23:46 UTCEPSS rescore
  7. 2026-08-20 22:52 UTCEPSS rescore
  8. 2026-08-20 02:45 UTCOSV refresh
  9. 2026-08-19 17:01 UTCEPSS rescore
  10. 2026-08-18 13:45 UTCEPSS rescore
  11. 2026-08-17 13:44 UTCEPSS rescore
  12. 2026-08-16 14:53 UTCEPSS rescore
  13. 2026-08-16 02:11 UTCEPSS rescore
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  15. 2026-08-15 01:27 UTCEPSS rescore
  16. 2026-08-13 21:57 UTCEPSS rescore
  17. 2026-08-12 13:47 UTCEPSS rescore
  18. 2026-08-11 13:38 UTCEPSS rescore
  19. 2026-08-09 13:43 UTCEPSS rescore
  20. 2026-08-08 16:33 UTCEPSS rescore
  21. 2026-08-07 16:23 UTCEPSS rescore
  22. 2026-08-06 13:43 UTCEPSS rescore
  23. 2026-08-05 19:14 UTCEPSS rescore
  24. 2026-08-04 21:48 UTCOSV refresh
  25. 2026-08-04 15:06 UTCEPSS rescore
  26. 2026-08-04 10:34 UTCEPSS rescore
  27. 2026-08-03 10:33 UTCEPSS rescore
  28. 2026-08-02 02:24 UTCEPSS rescore
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  30. 2026-07-30 16:25 UTCEPSS rescore
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  37. 2026-07-25 14:15 UTCEPSS rescore
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  39. 2026-07-23 14:16 UTCEPSS rescore
  40. 2026-07-23 02:00 UTCEG score recompute
  41. 2026-07-22 22:47 UTCEG score recompute
  42. 2026-07-22 14:06 UTCEPSS rescore
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  44. 2026-07-21 15:22 UTCEPSS rescore
  45. 2026-07-21 15:22 UTCEPSS rescore
  46. 2026-07-20 17:05 UTCEPSS rescore
  47. 2026-07-19 14:28 UTCEPSS rescore
  48. 2026-07-19 02:27 UTCEPSS rescore
  49. 2026-07-19 02:27 UTCEPSS rescore
  50. 2026-07-18 19:59 UTCOSV refresh
  51. 2026-07-18 10:02 UTCEPSS rescore
  52. 2026-07-18 10:02 UTCEPSS rescore
  53. 2026-07-16 17:00 UTCEPSS rescore
  54. 2026-07-15 16:55 UTCEPSS rescore
  55. 2026-07-15 16:55 UTCEPSS rescore
  56. 2026-07-15 01:58 UTCEPSS rescore
  57. 2026-07-13 22:27 UTCEPSS rescore
  58. 2026-07-13 22:27 UTCEPSS rescore
  59. 2026-07-13 06:10 UTCEPSS rescore
  60. 2026-07-12 05:44 UTCEPSS rescore
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  62. 2026-07-11 08:25 UTCEPSS rescore
  63. 2026-07-11 08:25 UTCEPSS rescore
  64. 2026-07-09 19:07 UTCEPSS rescore
  65. 2026-07-08 15:12 UTCEPSS rescore
  66. 2026-07-07 13:43 UTCEPSS rescore
  67. 2026-07-06 16:25 UTCEPSS rescore
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  69. 2026-07-06 02:21 UTCEPSS rescore
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  71. 2026-07-05 02:28 UTCEPSS rescore
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  74. 2026-07-02 16:57 UTCEPSS rescore
  75. 2026-07-01 15:03 UTCEPSS rescore

Frequently asked(5)

What is CVE-2021-31439?
CVE-2021-31439 is a high vulnerability published on May 21, 2021. 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…
When was CVE-2021-31439 disclosed?
CVE-2021-31439 was first published in the National Vulnerability Database on May 21, 2021, with the most recent update on January 14, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-31439 actively exploited?
CVE-2021-31439 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 2% probability of exploitation in the next 30 days, which ranks it in the top 17.2% of all scored CVEs.
What is the CVSS score of CVE-2021-31439?
CVE-2021-31439 has a CVSS v3 base score of 8.8 (NVD).
How do I remediate CVE-2021-31439?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-31439, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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