CVE-2021-46935
In the Linux kernel, the following vulnerability has been resolved: binder: fix async_free_space accounting for empty parcels In 4.13, commit 74310e06be4d ("android: binder: Move buffer out of area shared with user space") fixed a kernel structure…
Does this matter?
Lower severity and a low EPSS score (0.23%). Track it; it rarely justifies an emergency change on its own.
Description
In the Linux kernel, the following vulnerability has been resolved: binder: fix async_free_space accounting for empty parcels In 4.13, commit 74310e06be4d ("android: binder: Move buffer out of area shared with user space") fixed a kernel structure visibility issue. As part of that patch, sizeof(void *) was used as the buffer size for 0-length data payloads so the driver could detect abusive clients sending 0-length asynchronous transactions to a server by enforcing limits on async_free_size. Unfortunately, on the "free" side, the accounting of async_free_space did not add the sizeof(void *) back. The result was that up to 8-bytes of async_free_space were leaked on every async transaction of 8-bytes or less. These small transactions are uncommon, so this accounting issue has gone undetected for several years. The fix is to use "buffer_size" (the allocated buffer size) instead of "size" (the logical buffer size) when updating the async_free_space during the free operation. These are the same except for this corner case of asynchronous transactions with payloads < 8 bytes.
- CVSS 3.1
- 5.5 MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
- EPSS
- 0.23% probability · 14th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-668
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/103b16a8c51f96d5fe063022869ea906c256e5daPatch
- https://git.kernel.org/stable/c/17691bada6b2f1d5f1c0f6d28cd9d0727023b0ffPatch
- https://git.kernel.org/stable/c/1cb8444f3114f0bb2f6e3bcadcf09aa4a28425d4Patch
- https://git.kernel.org/stable/c/2d2df539d05205fd83c404d5f2dff48d36f9b495Patch
- https://git.kernel.org/stable/c/7c7064402609aeb6fb11be1b4ec10673ff17b593Patch
- https://git.kernel.org/stable/c/cfd0d84ba28c18b531648c9d4a35ecca89ad9901Patch
- https://git.kernel.org/stable/c/103b16a8c51f96d5fe063022869ea906c256e5daPatch
- https://git.kernel.org/stable/c/17691bada6b2f1d5f1c0f6d28cd9d0727023b0ffPatch
- https://git.kernel.org/stable/c/1cb8444f3114f0bb2f6e3bcadcf09aa4a28425d4Patch
- https://git.kernel.org/stable/c/2d2df539d05205fd83c404d5f2dff48d36f9b495Patch
- https://git.kernel.org/stable/c/7c7064402609aeb6fb11be1b4ec10673ff17b593Patch
- https://git.kernel.org/stable/c/cfd0d84ba28c18b531648c9d4a35ecca89ad9901Patch
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.