Vulnerability in Qemu
CVE-2021-20257
An infinite loop flaw was found in the e1000 NIC emulator of the QEMU. This issue occurs while processing transmits (tx) descriptors in process_tx_desc if various descriptor fields are initialized with invalid values. This flaw allows a guest to consume CPU cycles on the host, resulting in a denial of service. The highest threat from this vulnerability is to system availability.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.004 (28.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 28th percentile — 28.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000
Affected products
- Qemu
- Debian Linux — versions 10.0
- Fedoraproject Fedora — versions 33
- Red Hat Codeready Linux Builder
- Red Hat Enterprise Linux — versions 6.0, 8.0
- Red Hat Enterprise Linux For IBM Z Systems — versions 8.0
- Red Hat Enterprise Linux For Power Little Endian — versions 8.0
- Red Hat OpenStack Platform — versions 10.0, 13.0
- Qemu — versions Fixed-In v6.2.0
Weakness classification (CWE)
Public proof-of-concept exploits
References
- www.openwall.com/lists/oss-security/2021/02/25/2 (Patch, Mailing List, Third Party Advisory)
- lists.gnu.org/archive/html/qemu-devel/2021-02/msg07428.html (Patch, Mailing List, Vendor Advisory)
- github.com/qemu/qemu/commit/3de46e6fc489c52c9431a8a832ad8170a7569bd8 (Patch, Third Party Advisory)
- bugzilla.redhat.com/show_bug.cgi (Patch, Third Party Advisory, Issue Tracking)
- security.netapp.com/advisory/ntap-20220425-0003/ (Third Party Advisory)
- security.gentoo.org/glsa/202208-27 (vendor-advisory, Third Party Advisory)
- lists.debian.org/debian-lts-announce/2022/09/msg00008.html (mailing-list, Mailing List, Third Party Advisory)
Frequently asked questions
- What is CVE-2021-20257?
- CVE-2021-20257 is a medium-severity vulnerability in Qemu, classified under Loop with Unreachable Exit Condition (Infinite Loop). CVSS score: 6.5/10. Published 2022-03-16.
- How severe is CVE-2021-20257?
- Medium severity. CVSS v3 base score is 6.5 out of 10.
- Is CVE-2021-20257 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.