CVE-2021-46935

Medium

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.

Package Linux Kernel
Published 2024-02-27
Last modified 2024-11-21
CVSS version 3.1
Patch available
Yes

CVSS 3.1 score

5.5

out of 10
Medium
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Weakness type

CWE-668

CVE-2021-46935 is classified as CWE-668

See CWE-668 on MITRE CWE for full details on this weakness type.

Affected versions

Linux kernel versions 4.14 and later are affected. Fixed in 4.14.261, 4.19.224, 5.4.170, 5.10.90, 5.15.13, 5.16 and their respective stable series.

Affected from
≥ 4.14
Fixed in
✓ 4.14.261 4.14.x ✓ 4.19.224 4.19.x ✓ 5.4.170 5.4.x ✓ 5.10.90 5.10.x ✓ 5.15.13 5.15.x ✓ 5.16

References

6 total
Showing 5 of 6 references View all on NVD

Frequently asked questions

  • What is CVE-2021-46935?

    CVE-2021-46935 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 . It affects Linux kernel versions from 4.14 onward and has been patched in 4.14.261, 4.19.224, 5.4.170 and others. CVE-2021-46935 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2021-46935?

    CVE-2021-46935 has a CVSS score of 5.5 out of 10, rated Medium severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N .

  • Is there a patch available for CVE-2021-46935?

    Yes. CVE-2021-46935 has been patched. Fixed versions include 4.14.261, 4.19.224, 5.4.170 and others. If you are running Linux kernel 4.14 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2021-46935 actively exploited?

    No. CVE-2021-46935 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

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