Snapdragon: Time-of-check Time-of-use (TOCTOU) Race Condition
CVE-2023-28576 is a high-severity time-of-check time-of-use (TOCTOU) race condition vulnerability in Snapdragon from Qualcomm, with a CVSS 3.1 base score of 7.0 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. Affected Snapdragon versions: FastConnect 6800; FastConnect 6900; FastConnect 7800, and others listed below. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.08% 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
- Check which version of Snapdragon you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on qualcomm.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Qualcomm | Snapdragon | FastConnect 6800; FastConnect 6900; FastConnect 7800; QCA6391; QCA6426; QCA6436; QCN9074; QCS410; and 23 more ranges | Not stated |
| Qualcomm | Fastconnect 6800 Firmware | Not specified in the record | Not stated |
| Qualcomm | Fastconnect 6900 Firmware | Not specified in the record | Not stated |
| Qualcomm | Fastconnect 7800 Firmware | Not specified in the record | Not stated |
| Qualcomm | Qca6391 Firmware | Not specified in the record | Not stated |
| Qualcomm | Qca6426 Firmware | Not specified in the record | Not stated |
| Qualcomm | Qca6436 Firmware | Not specified in the record | Not stated |
| Qualcomm | Qcn9074 Firmware | Not specified in the record | Not stated |
| Qualcomm | Qcs410 Firmware | Not specified in the record | Not stated |
| Qualcomm | Qcs610 Firmware | Not specified in the record | Not stated |
| Qualcomm | Sd865 5g Firmware | Not specified in the record | Not stated |
| Qualcomm | Snapdragon 8 Gen 1 Firmware | Not specified in the record | Not stated |
| Qualcomm | Snapdragon 865 5g Firmware | Not specified in the record | Not stated |
| Qualcomm | Snapdragon 870 5g Firmware | Not specified in the record | Not stated |
| Qualcomm | Snapdragon X55 5g Firmware | Not specified in the record | Not stated |
| Qualcomm | Snapdragon Xr2 5g Firmware | Not specified in the record | Not stated |
| Qualcomm | Sw5100 Firmware | Not specified in the record | Not stated |
| Qualcomm | Sw5100p Firmware | Not specified in the record | Not stated |
| Qualcomm | Sxr2130 Firmware | Not specified in the record | Not stated |
| Qualcomm | Wcd9341 Firmware | Not specified in the record | Not stated |
| Qualcomm | Wcd9370 Firmware | Not specified in the record | Not stated |
| Qualcomm | Wcd9380 Firmware | Not specified in the record | Not stated |
| Qualcomm | Wcn3660b Firmware | Not specified in the record | Not stated |
| Qualcomm | Wcn3680b Firmware | Not specified in the record | Not stated |
| Qualcomm | Wcn3950 Firmware | Not specified in the record | Not stated |
Version data comes from the organisation that assigned the CVE; 6 further products are omitted here. 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
- HighSuccess depends on conditions outside the attacker's control.
- 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:H/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 6.4 | Medium | CNA (qualcomm.com) |
| CVSS 3.1 | 7.0 | High | NVD |
Official description
The buffer obtained from kernel APIs such as cam_mem_get_cpu_buf() may be readable/writable in userspace after kernel accesses it. In other words, user mode may race and modify the packet header (e.g. header.count), causing checks (e.g. size checks) in kernel code to be invalid. This may lead to out-of-bounds read/write issues.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Time-of-check Time-of-use (TOCTOU) Race Condition
The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check.
How developers prevent this class of flaw
- The most basic advice for TOCTOU vulnerabilities is to not perform a check before the use. This does not resolve the underlying issue of the execution of a function on a resource whose state and identity cannot be assured, but it does help to limit the false sense of security given by the check.
- When the file being altered is owned by the current user and group, set the effective gid and uid to that of the current user and group when executing this statement.
- Limit the interleaving of operations on files from multiple processes.
More Time-of-check Time-of-use (TOCTOU) Race Condition vulnerabilities (CWE-367)
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
Other vulnerabilities in Snapdragon
- 7.1 High severity
- 7.0 High severity
Recent Time-of-check Time-of-use (TOCTOU) Race Condition vulnerabilities
- 7.5 High severity
- 7.0 High severity
- 7.0 High severity
- 7.0 High severity
- 7.0 High severity
- 7.0 High severity
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