What’s Vulnerable › Vulnerabilities

CVE-2020-29534

• Severity: high (CVSS 7.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2020-12-03 · updated 2026-06-17

Description

An issue was discovered in the Linux kernel before 5.9.3. io_uring takes a non-refcounted reference to the files_struct of the process that submitted a request, causing execve() to incorrectly optimize unshare_fd(), aka CID-0f2122045b94.

Affected products

• Linux kernel: from 5.1 before 5.8.18; from 5.9.0 before 5.9.3; 5.10-rc1 — fixed in 5.8.18, 5.9.3

How to fix

Upgrade to a fixed version: Linux kernel 5.8.18, 5.9.3. Check the vendor advisory for mitigations.

References

• https://bugs.chromium.org/p/project-zero/issues/detail?id=2089
• https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.9.3
• https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0f2122045b946241a9e549c2a76cea54fa58a7ff
• https://bugs.chromium.org/p/project-zero/issues/detail?id=2089
• https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.9.3
• https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0f2122045b946241a9e549c2a76cea54fa58a7ff

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