U.S. flag   An official website of the United States government
Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Https

Secure .gov websites use HTTPS
A lock (Dot gov) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2021-46988 Detail

Description

In the Linux kernel, the following vulnerability has been resolved: userfaultfd: release page in error path to avoid BUG_ON Consider the following sequence of events: 1. Userspace issues a UFFD ioctl, which ends up calling into shmem_mfill_atomic_pte(). We successfully account the blocks, we shmem_alloc_page(), but then the copy_from_user() fails. We return -ENOENT. We don't release the page we allocated. 2. Our caller detects this error code, tries the copy_from_user() after dropping the mmap_lock, and retries, calling back into shmem_mfill_atomic_pte(). 3. Meanwhile, let's say another process filled up the tmpfs being used. 4. So shmem_mfill_atomic_pte() fails to account blocks this time, and immediately returns - without releasing the page. This triggers a BUG_ON in our caller, which asserts that the page should always be consumed, unless -ENOENT is returned. To fix this, detect if we have such a "dangling" page when accounting fails, and if so, release it before returning.


Metrics

 
NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

References to Advisories, Solutions, and Tools

By selecting these links, you will be leaving NIST webspace. We have provided these links to other web sites because they may have information that would be of interest to you. No inferences should be drawn on account of other sites being referenced, or not, from this page. There may be other web sites that are more appropriate for your purpose. NIST does not necessarily endorse the views expressed, or concur with the facts presented on these sites. Further, NIST does not endorse any commercial products that may be mentioned on these sites. Please address comments about this page to [email protected].

URL Source(s) Tag(s)
https://git.kernel.org/stable/c/07c9b834c97d0fa3402fb7f3f3b32df370a6ff1f CVE, kernel.org Patch 
https://git.kernel.org/stable/c/140cfd9980124aecb6c03ef2e69c72d0548744de CVE, kernel.org Patch 
https://git.kernel.org/stable/c/2d59a0ed8b26b8f3638d8afc31f839e27759f1f6 CVE, kernel.org Patch 
https://git.kernel.org/stable/c/319116227e52d49eee671f0aa278bac89b3c1b69 CVE, kernel.org Patch 
https://git.kernel.org/stable/c/7ed9d238c7dbb1fdb63ad96a6184985151b0171c CVE, kernel.org Patch 
https://git.kernel.org/stable/c/ad53127973034c63b5348715a1043d0e80ceb330 CVE, kernel.org Patch 
https://git.kernel.org/stable/c/b3f1731c6d7fbc1ebe3ed8eff6d6bec56d76ff43 CVE, kernel.org Patch 

Weakness Enumeration

CWE-ID CWE Name Source
CWE-416 Use After Free cwe source acceptance level NIST  

Known Affected Software Configurations Switch to CPE 2.2

CPEs loading, please wait.

Denotes Vulnerable Software
Are we missing a CPE here? Please let us know.

Change History

6 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2021-46988
NVD Published Date:
02/28/2024
NVD Last Modified:
12/26/2024
Source:
kernel.org