A NULL pointer dereference flaw was found in the floppy disk emulator of QEMU. This issue occurs while processing read/write ioport…

Description

A NULL pointer dereference flaw was found in the floppy disk emulator of QEMU. This issue occurs while processing read/write ioport commands if the selected floppy drive is not initialized with a block device. This flaw allows a privileged guest user to crash the QEMU process on the host, resulting in a denial of service. The highest threat from this vulnerability is to system availability.

Scores

EPSS (exploitation in 30 days)

0.48% · top 58% of all CVEs (7 Nov 2026)

The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.5.

Weakness

• CWE-476 (opens in a new tab)All about CWE-476 and its CVEs

Affected products

• qemu

  • affected vulnerable up to (including) qemu 5.2.0

References (5)

• https://bugs.launchpad.net/qemu/+bug/1912780 (opens in a new tab)x_refsource_MISCx_transferred
• https://www.openwall.com/lists/oss-security/2021/01/28/1 (opens in a new tab)x_refsource_MISCx_transferred
• https://security.netapp.com/advisory/ntap-20210708-0004/ (opens in a new tab)x_refsource_CONFIRMx_transferred
• [debian-lts-announce] 20220404 [SECURITY] [DLA 2970-1] qemu security update (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
• [debian-lts-announce] 20220905 [SECURITY] [DLA 3099-1] qemu security update (opens in a new tab)mailing-listx_refsource_MLISTx_transferred

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2021-20196](https://trackcve.app/badge/CVE-2021-20196.svg)](https://trackcve.app/cve/CVE-2021-20196)

Record last updated 3 Aug 2024, 17:30 UTC.