Linux: Buffer Copy without Checking Size of Input
CVE-2022-49754 is a high-severity buffer copy without checking size of input vulnerability in Linux, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions ed818fd8c531abf561b379995ee7cc4c68029464, 2185e0fdbb2137f22a9dd9fcbf6481400d56299b as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.21% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to ed818fd8c531abf561b379995ee7cc4c68029464 or 2185e0fdbb2137f22a9dd9fcbf6481400d56299b, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.1.9 or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | b338d91703fae6f6afd67f3f75caa3b8f36ddef3 up to, but not including, ed818fd8c531abf561b379995ee7cc4c68029464; b338d91703fae6f6afd67f3f75caa3b8f36ddef3 up to, but not including, 2185e0fdbb2137f22a9dd9fcbf6481400d56299b; 6.1 | ed818fd8c531abf561b379995ee7cc4c68029464, 2185e0fdbb2137f22a9dd9fcbf6481400d56299b |
| Linux | Linux Kernel | 6.1 up to, but not including, 6.1.9; 6.2 | 6.1.9 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.8 | High | NVD |
| CVSS 3.1 | 7.8 | High | CISA (ADP) |
Official description
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: Fix a buffer overflow in mgmt_mesh_add() Smatch Warning: net/bluetooth/mgmt_util.c:375 mgmt_mesh_add() error: __memcpy() 'mesh_tx->param' too small (48 vs 50) Analysis: 'mesh_tx->param' is array of size 48. This is the destination. u8 param[sizeof(struct mgmt_cp_mesh_send) + 29]; // 19 + 29 = 48. But in the caller 'mesh_send' we reject only when len > 50. len > (MGMT_MESH_SEND_SIZE + 31) // 19 + 31 = 50.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Buffer Copy without Checking Size of Input
The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer.
How developers prevent this class of flaw
- Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer. Be wary that a language's interface to native code may still be subject to overflows, even if the language itself is theoretically safe.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Examples include the Safe C String Library (SafeStr) by Messier and Viega, and the Strsafe.h library from Microsoft. These libraries provide safer versions of overflow-prone string-handling functions.
- Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.
More Buffer Copy without Checking Size of Input vulnerabilities (CWE-120)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Recent Buffer Copy without Checking Size of Input vulnerabilities
- 7.5 High severity
- 9.8 Critical severity
- 7.8 High severity
- 9.8 Critical severity
- 7.8 High severity
- 7.5 High severity
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