Linux: Out-of-bounds Write
CVE-2023-52531 is a high-severity out-of-bounds write 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 7c8faa31080342aec4903c9acb20caf82fcca1ef, 6b3223449c959a8be94a1f042288059e40fcccb0, f06cdd8d4ba5252986f51f80cc30263636397128 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 0.24% 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 7c8faa31080342aec4903c9acb20caf82fcca1ef or 6b3223449c959a8be94a1f042288059e40fcccb0 or f06cdd8d4ba5252986f51f80cc30263636397128 or 8ba438ef3cacc4808a63ed0ce24d4f0942cfe55d, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.15.135 or 6.1.57 or 6.5.7, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 8ca151b568b67a7b72dcfc6ee6ea7c107ddd795c up to, but not including, 7c8faa31080342aec4903c9acb20caf82fcca1ef; 8ca151b568b67a7b72dcfc6ee6ea7c107ddd795c up to, but not including, 6b3223449c959a8be94a1f042288059e40fcccb0; 8ca151b568b67a7b72dcfc6ee6ea7c107ddd795c up to, but not including, f06cdd8d4ba5252986f51f80cc30263636397128; 8ca151b568b67a7b72dcfc6ee6ea7c107ddd795c up to, but not including, 8ba438ef3cacc4808a63ed0ce24d4f0942cfe55d; 3.9 | 7c8faa31080342aec4903c9acb20caf82fcca1ef, 6b3223449c959a8be94a1f042288059e40fcccb0, f06cdd8d4ba5252986f51f80cc30263636397128, 8ba438ef3cacc4808a63ed0ce24d4f0942cfe55d |
| Linux | Linux Kernel | 3.9 up to, but not including, 5.15.135; 5.16 up to, but not including, 6.1.57; 6.2 up to, but not including, 6.5.7; 6.6 | 5.15.135, 6.1.57, 6.5.7 |
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.
Official description
In the Linux kernel, the following vulnerability has been resolved: wifi: iwlwifi: mvm: Fix a memory corruption issue A few lines above, space is kzalloc()'ed for: sizeof(struct iwl_nvm_data) + sizeof(struct ieee80211_channel) + sizeof(struct ieee80211_rate) 'mvm->nvm_data' is a 'struct iwl_nvm_data', so it is fine. At the end of this structure, there is the 'channels' flex array. Each element is of type 'struct ieee80211_channel'. So only 1 element is allocated in this array. When doing: mvm->nvm_data->bands[0].channels = mvm->nvm_data->channels; We point at the first element of the 'channels' flex array. So this is fine. However, when doing: mvm->nvm_data->bands[0].bitrates = (void *)((u8 *)mvm->nvm_data->channels + 1); because of the "(u8 *)" cast, we add only 1 to the address of the beginning of the flex array. It is likely that we want point at the 'struct ieee80211_rate' allocated just after. Remove the spurious casting so that the pointer arithmetic works as expected.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Out-of-bounds Write
The product writes data past the end, or before the beginning, of the intended 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.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Recent Out-of-bounds Write vulnerabilities
- 9.8 Critical severity
- 9.8 Critical severity
- 7.5 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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