VulnerabilityPublished 18 Jun 2025Updated 14 Nov 2025

CVE-2025-38033: Linux kernel · x86/Kconfig: make CFI_AUTO_DEFAULT depend on !RUST or Rust >= 1.88

Source GCVE Database

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Not known to be exploited · CVSS 5.5 Medium.

Data as of 13 Nov 2026, 18:51 UTC

CVSS 3.1 base score

5.5Medium

How severe the flaw is on the 0–10 CVSS scale.

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Attack Vector: Local
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Local: The vulnerable component is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either: the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or remotely (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., tricking a legitimate user into opening a malicious document).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 18 Jun 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 13 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

ghsa-gxj3-8g3m-8hpw

What to do

AI-suggested

A fix is available by configuring the kernel so that CFI_AUTO_DEFAULT depends on Rust being disabled or Rust version 1.88 or higher. Rust 1.88, scheduled for release in June 2025, addresses the underlying CFI violation. Users should upgrade to Rust 1.88 or later and ensure their kernel configuration reflects this dependency to avoid kernel panics. No additional mitigation is required beyond applying this configuration and using the fixed Rust version.

Description

A vulnerability in the Linux kernel's x86 configuration allows a kernel panic when Rust code calls core::fmt::write() with FineIBT enabled. This occurs because core::fmt::rt::Argument::fmt() disables Control Flow Integrity (CFI), causing a Control Protection exception under FineIBT. The issue is addressed by making CFI_AUTO_DEFAULT depend on either Rust being disabled or Rust version 1.88 or higher, which fixes the incompatibility. Rust 1.88 is scheduled for release in June 2025 and is expected to resolve this problem.

Impact

The vulnerability causes a kernel panic (denial of service) when Rust code calls core::fmt::write() with FineIBT enabled, due to a Control Protection exception triggered by disabled CFI in Rust's formatting code. This affects system stability and reliability but does not directly impact confidentiality or integrity.

Summary

The Linux kernel vulnerability CVE-2025-38033 arises from an incompatibility between Rust code and the FineIBT kernel feature. Specifically, calling core::fmt::write() from Rust triggers a kernel panic due to disabled CFI in core::fmt::rt::Argument::fmt(), which violates FineIBT's control flow protections. The kernel patch introduces a Kconfig dependency to prevent FineIBT from being enabled by default when Rust is enabled unless Rust version is 1.88 or later, where the Rust core library fixes this issue. This prevents kernel panics caused by Control Protection exceptions when Rust code executes formatting functions under FineIBT.

References

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