What’s Vulnerable › Vulnerabilities

CVE-2022-34746

• Severity: medium (CVSS 5.9 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2022-09-20 · updated 2026-06-17
• Weakness: CWE-331

Description

An insufficient entropy vulnerability caused by the improper use of randomness sources with low entropy for RSA key pair generation was found in Zyxel GS1900 series firmware versions prior to V2.70. This vulnerability could allow an unauthenticated attacker to retrieve a private key by factoring the RSA modulus N in the certificate of the web administration interface.

Affected products

• Zyxel GS1900-10HP firmware: before 2.70\(aazi.3\)c0 — fixed in 2.70\(aazi.3\)c0
• Zyxel GS1900-16 firmware: before 2.70\(aahj.3\)c0 — fixed in 2.70\(aahj.3\)c0
• Zyxel GS1900-24 firmware: before 2.70\(aahl.3\)c0 — fixed in 2.70\(aahl.3\)c0
• Zyxel GS1900-24E firmware: before 2.70\(aahk.3\)c0 — fixed in 2.70\(aahk.3\)c0
• Zyxel GS1900-24EP firmware: before 2.70\(abto.3\)c0 — fixed in 2.70\(abto.3\)c0
• Zyxel GS1900-24HPv2 firmware: before 2.70\(abtp.3\)c0 — fixed in 2.70\(abtp.3\)c0
• Zyxel GS1900-48 firmware: before 2.70\(aahn.3\)c0 — fixed in 2.70\(aahn.3\)c0
• Zyxel GS1900-48HPv2 firmware: before 2.70\(abtq.3\)c0 — fixed in 2.70\(abtq.3\)c0
• Zyxel GS1900-8 firmware: before 2.70\(aahh.3\)c0 — fixed in 2.70\(aahh.3\)c0
• Zyxel GS1900-8HP firmware: before 2.70\(aahi.3\)c0 — fixed in 2.70\(aahi.3\)c0

How to fix

Upgrade to a fixed version: Zyxel GS1900-10HP firmware 2.70\(aazi.3\)c0; Zyxel GS1900-16 firmware 2.70\(aahj.3\)c0; Zyxel GS1900-24 firmware 2.70\(aahl.3\)c0; Zyxel GS1900-24E firmware 2.70\(aahk.3\)c0; Zyxel GS1900-24EP firmware 2.70\(abto.3\)c0; Zyxel GS1900-24HPv2 firmware 2.70\(abtp.3\)c0; Zyxel GS1900-48 firmware 2.70\(aahn.3\)c0; Zyxel GS1900-48HPv2 firmware 2.70\(abtq.3\)c0; Zyxel GS1900-8 firmware 2.70\(aahh.3\)c0; Zyxel GS1900-8HP firmware 2.70\(aahi.3\)c0. Check the vendor advisory for mitigations.

References

• https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-insufficient-entropy-vulnerability-of-gs1900-series-switches
• https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-insufficient-entropy-vulnerability-of-gs1900-series-switches

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