CVE-2021-26930 Memory corruption in n/a

What is CVE-2021-26930?

CVE-2021-26930 is a high-severity memory corruption vulnerability in Debian Debian Linux, published on 17 Feb 2021. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

An issue was discovered in the Linux kernel 3.11 through 5.10.16, as used by Xen. To service requests to the PV backend, the driver maps grant references provided by the frontend. In this process, errors may be encountered. In one case, an error encountered earlier might be discarded by later processing, resulting in the caller assuming successful mapping, and hence subsequent operations trying to access space that wasn't mapped. In another case, internal state would be insufficiently updated, preventing safe recovery from the error. This affects drivers/block/xen-blkback/blkback.c.

Which versions are affected by CVE-2021-26930?

It affects 3 products.

Products include Debian Debian Linux, Fedoraproject Fedora, Linux kernel.

How do I fix CVE-2021-26930?

Apply the vendor's patch.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2021-26930 being exploited?

There is no known exploitation of CVE-2021-26930 in the wild and no public exploit code.

Other vulnerabilities in Debian Debian Linux

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• CVE-2026-24061 GNU InetUtils Argument Injection Exploited Critical 9.8
• CVE-2025-39682 Linux Kernel Improper Check for Unusual or Exceptional Conditions Exploited Critical 9.8
• CVE-2024-9680 Mozilla Firefox Use-After-Free Exploited Critical 9.8

All Debian Debian Linux vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2021-26930, GHSA-2q89-537g-gjqw, UBUNTU-CVE-2021-26930.