CVE-2023-3959
Published: 08 November 2023
Summary
CVE-2023-3959 is a critical-severity Stack-based Buffer Overflow (CWE-121) vulnerability in Zavio Cf7500 Firmware. Its CVSS base score is 9.8 (Critical).
Operationally, ranked in the top 33.7% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
Deeper analysis
Zavio IP cameras including the CF7500, CF7300, CF7201, CF7501, CB3211, CB3212, CB5220, CB6231, B8520, B8220, and CD321 models running firmware version M2.1.6.05 contain multiple stack-based buffer overflows. The flaws occur during processing of XML elements received over the network, where the firmware fails to validate buffer sizes before writing data, resulting in out-of-bounds writes as described by CWE-121 and CWE-787. The issues carry a CVSS 3.1 score of 9.8.
An unauthenticated attacker with network access can send specially crafted XML requests to trigger the overflows and achieve remote code execution on the affected cameras. No user interaction or credentials are required, and the attack can be performed remotely with low complexity.
CISA has published ICS advisory ICSA-23-304-03 detailing the affected devices and associated risks.
The EPSS score for this CVE rose from a low baseline to a peak of 0.5954 on 2025-01-22 before receding to its current value of 0.0050, indicating a period of increased exploitation interest well after initial disclosure.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2023-44584
Vulnerability details
Zavio CF7500, CF7300, CF7201, CF7501, CB3211, CB3212, CB5220, CB6231, B8520, B8220, and CD321 IP Cameras with firmware version M2.1.6.05 are vulnerable to multiple instances of stack-based overflows. While processing XML elements from incoming network requests, the product does not sufficiently…
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check or validate allocated buffer size. This may lead to remote code execution.
- CWE(s)
Related Threats
No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Out-of-bounds writes that corrupt control flow or inject shellcode are rendered non-executable by the same memory protections.