CVE-2021-3491
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)
Linux kernel io_uring PROVIDE_BUFFERS MAX_RW_COUNT bypass
The io_uring subsystem in the Linux kernel allowed the MAX_RW_COUNT limit to be bypassed in the PROVIDE_BUFFERS operation, which led to negative values being usedin mem_rw when reading /proc/<PID>/mem. This could be used to create a heap overflow leading to arbitrary code execution in the kernel. It was addressed via commit d1f82808877b ("io_uring: truncate lengths larger than MAX_RW_COUNT on provide buffers") (v5.13-rc1) and backported to the stable kernels in v5.12.4, v5.11.21, and v5.10.37. It was introduced in ddf0322db79c ("io_uring: add IORING_OP_PROVIDE_BUFFERS") (v5.7-rc1).
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 kernel
- Vendor
- Linux
- Product
- Linux kernel
- Platforms
- Unknown
- Default status
Unknown
| Version (version) | Status (status) | Version scheme (versionType) | Exclusive end (lessThan) | Inclusive end (lessThanOrEqual) | Status changes (at → status) |
|---|---|---|---|---|---|
| trunk | affected | custom | v5.13-rc4 | Unavailable | None listed |
| linux-5.12.y | affected | custom | v5.12.4 | Unavailable | None listed |
| linux-5.11.y | affected | custom | v5.11.21 | Unavailable | None listed |
| linux-5.10.y | affected | custom | v5.10.37 | Unavailable | None listed |
| v5.7-rc1 | affected | custom | 5.7* | Unavailable | None listed |