Linux: Reachable Assertion
CVE-2025-39803 is a high-severity reachable assertion 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 c0cc24c139e0f62859dbf88e050ba074cd93988f, e5203d89d59bfcbe1f348aa0d2dc4449a8ba644c 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 0.15% 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 c0cc24c139e0f62859dbf88e050ba074cd93988f or e5203d89d59bfcbe1f348aa0d2dc4449a8ba644c, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.16.4 or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | fcd8b0450a9acbf3f0e88d749a72ef932df97663 up to, but not including, c0cc24c139e0f62859dbf88e050ba074cd93988f; fcd8b0450a9acbf3f0e88d749a72ef932df97663 up to, but not including, e5203d89d59bfcbe1f348aa0d2dc4449a8ba644c; 6.13 | c0cc24c139e0f62859dbf88e050ba074cd93988f, e5203d89d59bfcbe1f348aa0d2dc4449a8ba644c |
| Linux | Linux Kernel | 6.13 up to, but not including, 6.16.4; 6.17 | 6.16.4 |
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: scsi: ufs: core: Remove WARN_ON_ONCE() call from ufshcd_uic_cmd_compl() The UIC completion interrupt may be disabled while an UIC command is being processed. When the UIC completion interrupt is reenabled, an UIC interrupt is triggered and the WARN_ON_ONCE(!cmd) statement is hit. Hence this patch that removes this kernel warning.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Reachable Assertion
The product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary.
How developers prevent this class of flaw
- If the assertion statement is required (e.g., for security or reliability), change the invoking code to avoid the conditions that trigger the assertion.
- Consider changing the assertion to some other less fatal error. This might not be easy to implement, since other code may be needed to handle the error.
- Make sensitive open/close operations non-reachable from directly user-controlled data (e.g. open/close resources)
Timeline
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Recent Reachable Assertion vulnerabilities
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
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