FreeBSD: Improperly Controlled Modification of Dynamically-Determined Object Attributes
CVE-2026-49428 is a high-severity improperly controlled modification of dynamically-determined object attributes vulnerability in FreeBSD, with a CVSS 3.1 base score of 8.4 out of 10. It can be exploited with local access to the system by an unauthenticated attacker, without any action from a user. The record lists versions p1, p11, p7 as the first without the flaw, so updating FreeBSD to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.34% 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 FreeBSD to p1 or p11 or p7 or p16, whichever matches your release line, or a later version.
- Read the advisory on security.freebsd.org for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| FreeBSD | FreeBSD | 15.1-RELEASE up to, but not including, p1; 15.0-RELEASE up to, but not including, p11; 14.4-RELEASE up to, but not including, p7; 14.3-RELEASE up to, but not including, p16 | p1, p11, p7, p16 |
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
- NoneNo account or login is needed.
- 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:N/UI:N/S:U/C:H/I:H/A:H. Scored by CISA (ADP).
Official description
Certain system calls, such open(2) with the O_TRUNC flag set, and fspacectl(2), could incorrectly free memory in largepage objects. These operations are not permitted on largepage objects, but the implementation did not verify this. An unprivileged local user can abuse the bug to access freed kernel memory. This can be exploited to escalate privileges.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improperly Controlled Modification of Dynamically-Determined Object Attributes
The product receives input from an upstream component that specifies multiple attributes, properties, or fields that are to be initialized or updated in an object, but it does not properly control which attributes can be modified.
How developers prevent this class of flaw
- If available, use features of the language or framework that allow specification of allowlists of attributes or fields that are allowed to be modified. If possible, prefer allowlists over denylists. For applications written with Ruby on Rails, use the attr_accessible (allowlist) or attr_protected (denylist) macros in each class that may be used in mass assignment.
- If available, use the signing/sealing features of the programming language to assure that deserialized data has not been tainted. For example, a hash-based message authentication code (HMAC) could be used to ensure that data has not been modified.
- For any externally-influenced input, check the input against an allowlist of internal object attributes or fields that are allowed to be modified.
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
Other vulnerabilities in FreeBSD
- 7.0 High severity
- 7.0 High severity
- 7.0 High severity
- 7.0 High severity
- 7.0 High severity
- 8.4 High severity
Recent Improperly Controlled Modification of Dynamically-Determined Object Attributes vulnerabilities
- 8.5 High severity
- 8.8 High severity
- 8.8 High severity
- 8.4 High severity
- 8.7 High severity
- 7.5 High severity
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