CVE-2024-38270

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-09-10 · updated 2026-06-17
Weakness: CWE-331

Description

An insufficient entropy vulnerability caused by the improper use of a randomness function with low entropy for web authentication tokens generation exists in the Zyxel GS1900-10HP firmware version V2.80(AAZI.0)C0. This vulnerability could allow a LAN-based attacker a slight chance to gain a valid session token if multiple authenticated sessions are alive.

Affected products

Zyxel GS1900-10HP firmware: before 2.80\(aazi.1\)c0 — fixed in 2.80\(aazi.1\)c0
Zyxel GS1900-16 firmware: before 2.80\(aahj.1\)c0 — fixed in 2.80\(aahj.1\)c0
Zyxel GS1900-24 firmware: through 2.80\(aahl.1\)c0
Zyxel GS1900-24E firmware: through 2.80\(aahk.1\)c0
Zyxel GS1900-24EP firmware: before 2.80\(abto.1\)c0 — fixed in 2.80\(abto.1\)c0
Zyxel GS1900-24HPv2 firmware: before 2.80\(abtp.1\)c0 — fixed in 2.80\(abtp.1\)c0
Zyxel GS1900-48 firmware: before 2.80\(aahn.1\)c0 — fixed in 2.80\(aahn.1\)c0
Zyxel GS1900-48HPv2 firmware: before 2.80\(abtq.1\)c0 — fixed in 2.80\(abtq.1\)c0
Zyxel GS1900-8 firmware: before 2.80\(aahh.1\)c0 — fixed in 2.80\(aahh.1\)c0
Zyxel GS1900-8HP firmware: before 2.80\(aahi.1\)c0 — fixed in 2.80\(aahi.1\)c0

How to fix

Upgrade to a fixed version: Zyxel GS1900-10HP firmware 2.80\(aazi.1\)c0; Zyxel GS1900-16 firmware 2.80\(aahj.1\)c0; Zyxel GS1900-24EP firmware 2.80\(abto.1\)c0; Zyxel GS1900-24HPv2 firmware 2.80\(abtp.1\)c0; Zyxel GS1900-48 firmware 2.80\(aahn.1\)c0; Zyxel GS1900-48HPv2 firmware 2.80\(abtq.1\)c0; Zyxel GS1900-8 firmware 2.80\(aahh.1\)c0; Zyxel GS1900-8HP firmware 2.80\(aahi.1\)c0. Check the vendor advisory for mitigations.

References

https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-insufficient-entropy-vulnerability-for-web-authentication-tokens-generation-in-gs1900-series-switches-09-10-2024

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