CVE-2021-46988
CVE.org · Published
- Record status
- Published
- Identifier year (not publication year)
- 2021
- Source publication
- Source updated
- Imported by cveboard
- Source snapshot
- cve_2026-10-24_midnight_baseline ·
CNA source text (English)
userfaultfd: release page in error path to avoid BUG_ON
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.
Scoped product and version facts
Fix information unknown; no fixed version is derived here. Missing information does not prove that no fix exists.
Exploitation unknown; this catalogue does not assess exploitation.
Linux
- Vendor
- Linux
- Product
- Linux
- Platforms
- Unknown
- Default status
unaffected
| Version (version) | Status (status) | Version scheme (versionType) | Exclusive end (lessThan) | Inclusive end (lessThanOrEqual) | Status changes (at → status) |
|---|---|---|---|---|---|
| cb658a453b9327ce96ce5222c24d162b5b65b564 | affected | git | 319116227e52d49eee671f0aa278bac89b3c1b69 | Unavailable | None listed |
| cb658a453b9327ce96ce5222c24d162b5b65b564 | affected | git | 07c9b834c97d0fa3402fb7f3f3b32df370a6ff1f | Unavailable | None listed |
| cb658a453b9327ce96ce5222c24d162b5b65b564 | affected | git | b3f1731c6d7fbc1ebe3ed8eff6d6bec56d76ff43 | Unavailable | None listed |
| cb658a453b9327ce96ce5222c24d162b5b65b564 | affected | git | 140cfd9980124aecb6c03ef2e69c72d0548744de | Unavailable | None listed |
| cb658a453b9327ce96ce5222c24d162b5b65b564 | affected | git | ad53127973034c63b5348715a1043d0e80ceb330 | Unavailable | None listed |
| cb658a453b9327ce96ce5222c24d162b5b65b564 | affected | git | 2d59a0ed8b26b8f3638d8afc31f839e27759f1f6 | Unavailable | None listed |
| cb658a453b9327ce96ce5222c24d162b5b65b564 | affected | git | 7ed9d238c7dbb1fdb63ad96a6184985151b0171c | Unavailable | None listed |
Linux
- Vendor
- Linux
- Product
- Linux
- Platforms
- Unknown
- Default status
affected
| Version (version) | Status (status) | Version scheme (versionType) | Exclusive end (lessThan) | Inclusive end (lessThanOrEqual) | Status changes (at → status) |
|---|---|---|---|---|---|
| 4.11 | affected | Unavailable | Unavailable | Unavailable | None listed |
| 0 | unaffected | semver | 4.11 | Unavailable | None listed |
| 4.14.233 | unaffected | semver | Unavailable | 4.14.* | None listed |
| 4.19.191 | unaffected | semver | Unavailable | 4.19.* | None listed |
| 5.4.120 | unaffected | semver | Unavailable | 5.4.* | None listed |
| 5.10.38 | unaffected | semver | Unavailable | 5.10.* | None listed |
| 5.11.22 | unaffected | semver | Unavailable | 5.11.* | None listed |
| 5.12.5 | unaffected | semver | Unavailable | 5.12.* | None listed |
| 5.13 | unaffected | original_commit_for_fix | Unavailable | * | None listed |