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CVE-2022-34747

32
FAUCET Score

CVE-2022-34747 is a critical format string vulnerability affecting Zyxel NAS326 firmware versions prior to V5.21(AAZF.12)C0. This flaw allows an unauthenticated, remote attacker to achieve arbitrary code execution by sending a specially crafted UDP packet to the device. With a CVSS score of 9.8, this vulnerability poses a severe risk due to its network-based attack vector, low complexity, and high impact on confidentiality, integrity, and availability. While there is no known public exploit code or active exploitation in the wild, the vulnerability has garnered significant community attention and media coverage, indicating its potential for future exploitation.

Impacted Technologies

VendorProductVersion(s)CPE
< 5.21\(aazf.12\)c0CPE matchmatch criteria
cpe:2.3:o:zyxel:nas326_firmware:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

9.8CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.54%
Probability of exploitation in next 30 days
EPSS Percentile
72.3%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0154 is in the 59th percentile among its peer group of 36,897 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Remediation records are not available for this CVE.

References

zyxel.com / support/Zyxel-security-advisory-for-format-string-vulnerability-in-NAS.shtml
PatchVendor Advisory