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    CVE-2021-3748

    A use-after-free vulnerability was found in the virtio-net device of QEMU. It could occur when the descriptor's address belongs to the non direct access region, due to num_buffers being set after the virtqueue elem has been unmapped. A malicious guest could use this flaw to crash QEMU, resulting in a denial of service condition, or potentially execute code on the host with the privileges of the QEMU process.

    Published:Aug 27, 2021
    Last Modified:Nov 21, 2024
    EPS:Mar 23, 2022
    EPSS Score:0.00028
    CVSS Score:7.5

    Affected Products

    Vendor
    Canonical
    Product
    Ubuntu Linux
    Vendor
    Debian
    Product
    Debian Linux
    Vendor
    Fedoraproject
    Product
    Fedora
    Vendor
    Qemu
    Product
    Qemu
    Vendor
    Redhat
    Product
    Advanced Virtualization
    Vendor
    Redhat
    Product
    Enterprise Linux
    Vendor
    Redhat
    Product
    Enterprise Linux Advanced Virtualization Eus

    Exploits

    No exploit reference

    Common Weakness Enumeration

    CWE-416 Use After Free

    Common Attack Pattern Enumeration and Classification (CAPEC)

    No CAPEC recorded yet

    Related CVEs

    CVE-2026-13476 (CVSS 7.3) — IBM Informix Dynamic Server 14.10, 15.0, and 12.10 could allow an unauthenticated user to execute arbitrary co…
    CVE-2026-13367 (CVSS 7.8) — IBM Informix Dynamic Server 14.10, and 15.0 contain a local privilege escalation vulnerability in the oninit s…
    CVE-2026-47337 (CVSS 3.3) — Ubuntu Linux 6.8, 6.17 and 7.0 contain SAUCE patches with a possible NULL pointer dereference in the handling …
    CVE-2026-47336 (CVSS 3.3) — Ubuntu Linux 6.8 contains SAUCE patches with a possible use of an uninitialized variable in AppArmor AF_INET/A…
    CVE-2026-47335 (CVSS 5.5) — Ubuntu Linux 6.8 contains SAUCE patches with a possible NULL pointer dereference in the handling of AppArmor n…
    CVE-2026-47334 (CVSS 5.5) — Ubuntu Linux 6.8, 6.17 and 7.0 contain AppArmor SAUCE patches which incorrectly sleep while holding a spinlock…
    CVE-2026-47333 (CVSS 7.8) — Ubuntu Linux 6.8, 6.17 and 7.0 contain AppArmor SAUCE patches which can potentially incorrectly compute the si…
    CVE-2026-47332 (CVSS 5.5) — Ubuntu Linux 6.8, 6.17 and 7.0 contain AppArmor SAUCE patches which incorrectly validate the size of an intern…
    CVE-2026-47331 (CVSS 7.8) — Ubuntu Linux 6.8 contains AppArmor SAUCE patches which fail to acquire a lock when modifying a linked list. An…
    CVE-2026-47330 (CVSS 3.3) — Ubuntu Linux 6.8, 7.17 and 7.0 contain AppArmor SAUCE patches which can, under certain circumstances, use an u…

    References

    https://bugzilla.redhat.com/show_bug.cgi?id=1998514
    https://github.com/qemu/qemu/commit/bedd7e93d01961fcb16a97ae45d93acf357e11f6
    https://lists.debian.org/debian-lts-announce/2022/04/msg00002.html
    https://lists.debian.org/debian-lts-announce/2022/09/msg00008.html
    https://lists.nongnu.org/archive/html/qemu-devel/2021-09/msg00388.html
    https://security.gentoo.org/glsa/202208-27
    https://security.netapp.com/advisory/ntap-20220425-0004/
    https://ubuntu.com/security/CVE-2021-3748
    https://bugzilla.redhat.com/show_bug.cgi?id=1998514
    https://github.com/qemu/qemu/commit/bedd7e93d01961fcb16a97ae45d93acf357e11f6
    https://lists.debian.org/debian-lts-announce/2022/04/msg00002.html
    https://lists.debian.org/debian-lts-announce/2022/09/msg00008.html
    https://lists.nongnu.org/archive/html/qemu-devel/2021-09/msg00388.html
    https://security.gentoo.org/glsa/202208-27
    https://security.netapp.com/advisory/ntap-20220425-0004/
    https://ubuntu.com/security/CVE-2021-3748

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High