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CVE-2026-32956NVD status: Analyzed

SD-330AC: Heap-based Buffer Overflow

CVE-2026-32956 is a critical-severity heap-based buffer overflow vulnerability in SD-330AC from Silex Technology, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected SD-330AC versions: Ver.1.42 and earlier. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.52% chance of exploitation within 30 days, which is low compared with other CVEs.

Patch this week

Critical severity: a successful attack would have severe impact.

What to do

  1. Update Sd-330ac Firmware to 1.50 or a later version.
  2. Read the advisory on silex.jp for workarounds and exact fixed builds.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
Silex TechnologySD-330ACVer.1.42 and earlierNot stated
Silex TechnologyAMC ManagerVer.5.0.2 and earlierNot stated
SilextechnologySd-330ac Firmwarebefore 1.501.50

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CNA (jpcert.or.jp).

Scoring systemScoreSeverityScored by
CVSS 4.09.3CriticalCNA (jpcert.or.jp)
CVSS 3.19.8CriticalCNA (jpcert.or.jp)

Official description

SD-330AC and AMC Manager provided by silex technology, Inc. contain a heap-based buffer overflow vulnerability in processing the redirect URLs. Arbitrary code may be executed on the device.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Heap-based Buffer Overflow

The product writes past the end of a buffer that was allocated on the heap.

How developers prevent this class of flaw

  • Pre-design: Use a language or compiler that performs automatic bounds checking.
  • Use an abstraction library to abstract away risky APIs. Not a complete solution.
  • Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.

More Heap-based Buffer Overflow vulnerabilities (CWE-122)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Third-party and government advisories

Other vulnerabilities in SD-330AC

All SD-330AC vulnerabilities

Recent Heap-based Buffer Overflow vulnerabilities

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