CVE-2021-47280
What it is
In the Linux kernel, the following vulnerability has been resolved: drm: Fix use-after-free read in drm_getunique() There is a time-of-check-to-time-of-use error in drm_getunique() due to retrieving file_priv->master prior to locking the device's master mutex. An example can be seen in the crash report of the use-after-free error found by Syzbot: https://syzkaller.appspot.com/bug?id=148d2f1dfac64af52ffd27b661981a540724f803 In the report, the master pointer was used after being freed. This is because another process had acquired the device's master mutex in drm_setmaster_ioctl(), then overwrote fpriv->master in drm_new_set_master(). The old value of fpriv->master was subsequently freed before the mutex was unlocked. To fix this, we lock the device's master mutex before retrieving the pointer from from fpriv->master. This patch passes the Syzbot reproducer test.
At a glance
- Exploitability
- Can be exploited locally on the machine with a low-privilege account. High risk of data exposure, data tampering, service disruption.
- Exploit odds
- 0.2% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.2% in the next 30 days (EPSS).
- Severity: 7.0 HIGH (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.2% · EPSS, next 30 days
- Weakness
- CWE-367
- Record status
- Analyzed
Affected
- Linux Kernel < 4.14.237
- Linux Kernel < 4.19.195
- Linux Kernel < 5.4.126
- Linux Kernel < 5.10.44
- Linux Kernel < 5.12.11
- Linux Kernel 5.13
Attack profile CVSS 3.1 · 7.0
- Attack vector
- Local
- Complexity
- High
- Privileges needed
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Raw vector
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2021-47280.md and follow it. Check whether this project is affected by CVE-2021-47280. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://git.kernel.org/stable/c/17dab9326ff263c62dab1dbac4492e2938a049e4
- https://git.kernel.org/stable/c/491d52e0078860b33b6c14f0a7ac74ca1b603bd6
- https://git.kernel.org/stable/c/7d233ba700ceb593905ea82b42dadb4ec8ef85e9
- https://git.kernel.org/stable/c/b246b4c70c1250e7814f409b243000f9c0bf79a3
- https://git.kernel.org/stable/c/b436acd1cf7fac0ba987abd22955d98025c80c2b
- https://git.kernel.org/stable/c/f773f8cccac13c7e7bbd9182e7996c727742488e
- https://git.kernel.org/stable/c/17dab9326ff263c62dab1dbac4492e2938a049e4
- https://git.kernel.org/stable/c/491d52e0078860b33b6c14f0a7ac74ca1b603bd6
- https://git.kernel.org/stable/c/7d233ba700ceb593905ea82b42dadb4ec8ef85e9
- https://git.kernel.org/stable/c/b246b4c70c1250e7814f409b243000f9c0bf79a3
References
- https://git.kernel.org/stable/c/17dab9326ff263c62dab1dbac4492e2938a049e4
- https://git.kernel.org/stable/c/491d52e0078860b33b6c14f0a7ac74ca1b603bd6
- https://git.kernel.org/stable/c/7d233ba700ceb593905ea82b42dadb4ec8ef85e9
- https://git.kernel.org/stable/c/b246b4c70c1250e7814f409b243000f9c0bf79a3
- https://git.kernel.org/stable/c/b436acd1cf7fac0ba987abd22955d98025c80c2b
- https://git.kernel.org/stable/c/f773f8cccac13c7e7bbd9182e7996c727742488e
- https://git.kernel.org/stable/c/17dab9326ff263c62dab1dbac4492e2938a049e4
- https://git.kernel.org/stable/c/491d52e0078860b33b6c14f0a7ac74ca1b603bd6
- https://git.kernel.org/stable/c/7d233ba700ceb593905ea82b42dadb4ec8ef85e9
- https://git.kernel.org/stable/c/b246b4c70c1250e7814f409b243000f9c0bf79a3
- https://git.kernel.org/stable/c/b436acd1cf7fac0ba987abd22955d98025c80c2b
- https://git.kernel.org/stable/c/f773f8cccac13c7e7bbd9182e7996c727742488e