CVE-2021-44052: Arbitrary file read

Severity: high (CVSS 8.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2022-05-05 · updated 2026-06-17
Weakness: CWE-59

Description

An improper link resolution before file access ('Link Following') vulnerability has been reported to affect QNAP device running QuTScloud, QuTS hero, and QTS. If exploited, this vulnerability allows remote attackers to traverse the file system to unintended locations and read or overwrite the contents of unexpected files. We have already fixed this vulnerability in the following versions of QuTScloud, QuTS hero, and QTS: QuTScloud c5.0.1.1998 and later QuTS hero h4.5.4.1971 build 20220310 and later QuTS hero h5.0.0.1986 build 20220324 and later QTS 4.3.4.1976 build 20220303 and later QTS 4.3.3.1945 build 20220303 and later QTS 4.2.6 build 20220304 and later QTS 4.3.6.1965 build 20220302 and later QTS 5.0.0.1986 build 20220324 and later QTS 4.5.4.1991 build 20220329 and later

Affected products

QNAP QTS: from 5.0.0.1716 before 5.0.0.1986; from 4.3.3.0174 before 4.3.3.1945; from 4.3.4.0899 before 4.3.4.1976; from 4.3.6.0895 before 4.3.6.1965; from 4.4.0.0883 before 4.5.4.1991; 4.2.6-build_20170517, 4.2.6-build_20190322, 4.2.6-build_20190730, 4.2.6-build_20190921, 4.2.6-build_20191107, 4.2.6-build_20200109 (+5) — fixed in 4.3.3.1945, 4.3.4.1976, 4.3.6.1965, 4.5.4.1991, 5.0.0.1986
QNAP Systems Inc. QuTS hero: before h4.5.4.1771; from h5.0.0.1772 before h5.0.0.1986 — fixed in h4.5.4.1771, h5.0.0.1986
QNAP Systems Inc. QuTScloud: before c5.0.1.1998 — fixed in c5.0.1.1998

How to fix

Upgrade to a fixed version: QNAP QTS 4.3.3.1945, 4.3.4.1976, 4.3.6.1965, 4.5.4.1991; QNAP Systems Inc. QuTS hero h4.5.4.1771, h5.0.0.1986; QNAP Systems Inc. QuTScloud c5.0.1.1998. Check the vendor advisory for mitigations.

References

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