Vulnerability · Published Jun 29, 2021 · Assigned by XEN

CVE-2021-28691

High 7.8

In plain English

A high-severity security flaw in Linux from Linux. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 30% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS NVD)7.8High

Exploit odds (30 days)0.4%top 69.6% of all CVEs

Exploited in the wildNo reportsnot in CISA KEV

Attack toolingNoneno public tooling known

Official description

Guest triggered use-after-free in Linux xen-netback A malicious or buggy network PV frontend can force Linux netback to disable the interface and terminate the receive kernel thread associated with queue 0 in response to the frontend sending a malformed packet. Such kernel thread termination will lead to a use-after-free in Linux netback when the backend is destroyed, as the kernel thread associated with queue 0 will have already exited and thus the call to kthread_stop will be performed against a stale pointer.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Debian:12	linux	5.10.46-1	DEBIAN-CVE-2021-28691
Debian:13	linux	5.10.46-1	DEBIAN-CVE-2021-28691
Debian:14	linux	5.10.46-1	DEBIAN-CVE-2021-28691

Affected products (as reported)

Vendor	Product	Versions
Linux	Linux	5.5.0 – before unspecified

References

https://xenbits.xenproject.org/xsa/advisory-374.txt x_refsource_MISC
GLSA-202107-30 vendor-advisory, x_refsource_GENTOO
https://security.netapp.com/advisory/ntap-20210805-0002/ x_refsource_CONFIRM