VulnerabilityPublished 22 Jan 2026

CVE-2026-23988: pbatard rufus · Time-of-check Time-of-use (TOCTOU) Race Condition

Affects pbatard rufusSource CVE Database V5

Not known to be exploited · CVSS 7.3 High : upgrade to 4.12_BETA soon.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score

7.3High

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 10% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 4.12_BETA

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

Attack Vector: Local
Attack Complexity: Low
Privileges Required: Low
User Interaction: Required
Scope: Unchanged
Confidentiality: High
Integrity: High
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: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
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: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to 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 22 Jan 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 Oct 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.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, 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.

What to do

Upgrade pbatard rufus to 4.12_BETA.

Affected software

Product	Affected	Fixed in
pbatardrufus	Affected <4.12_BETA	Fixed in 4.12_BETA
GitHubpbatard/rufus`pkg:github/pbatard/rufus`Other threats	Affected <=4.11	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

To mitigate CVE-2026-23988, European organizations should immediately upgrade Rufus to version 4.12_BETA or later, where the vulnerability is fixed. Until upgrades are deployed, restrict write permissions to the %TEMP% directory during Rufus execution to prevent unauthorized script replacement. Implement application whitelisting and endpoint protection to monitor and block unauthorized script executions. Enforce the principle of least privilege by limiting local user permissions and restricting the ability to run Rufus or similar utilities to trusted administrators only. Employ monitoring and alerting for suspicious file modifications in temporary directories. Educate users about the risks of running outdated Rufus versions and the importance of applying updates promptly. In environments with shared workstations, consider isolating user sessions or using virtualization to reduce the risk of local privilege escalation. Regularly audit installed software versions and patch management processes to ensure timely vulnerability remediation.

Description

CVE-2026-23988 is a high-severity TOCTOU race condition vulnerability in Rufus versions 4.11 and below. Rufus, a popular utility for creating bootable USB drives, runs with Administrator privileges but writes a PowerShell script to the user-writable %TEMP% directory without proper file locking. This allows a local attacker to replace the legitimate script with a malicious one between the write and execution steps, leading to arbitrary code execution with elevated privileges. The vulnerability requires local access and some user interaction but can result in full system compromise. It has been fixed in version 4.12_BETA. No known exploits are currently reported in the wild. European organizations using vulnerable Rufus versions on Windows systems are at risk, especially those with shared or multi-user environments. Mitigation involves upgrading Rufus to 4.

Impact

For European organizations, the impact of CVE-2026-23988 can be significant, especially in sectors relying heavily on Windows-based systems and USB boot media creation, such as IT service providers, government agencies, and enterprises with complex endpoint management. Successful exploitation allows local attackers to escalate privileges to Administrator level, potentially leading to full system compromise, data theft, unauthorized changes, or deployment of persistent malware. This risk is heightened in shared workstation environments, development labs, or organizations with less stringent endpoint controls. The vulnerability could facilitate lateral movement within networks if attackers gain initial footholds on lower-privileged accounts. Additionally, organizations relying on Rufus for secure USB media creation might face risks of supply chain compromise or tampering with bootable media. Although no exploits are currently known in the wild, the ease of exploitation and high impact warrant proactive mitigation to prevent potential attacks.

CWE-367Time-of-check Time-of-use (TOCTOU) Race Condition (opens in a new tab)
Base weaknessLikelihood of exploit: Medium
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.
Implementation
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.
Implementation
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.
Architecture and Design
Limit the interleaving of operations on files from multiple processes.
OWASP Cheat Sheets
Abuse Case (opens in a new tab)
OWASP ASVS 4.0.3
V1.11.3 (opens in a new tab)
V11.1.6 (opens in a new tab)
V1.11.2 (opens in a new tab)
Attack patterns
Leveraging Race Conditions via Symbolic Links (opens in a new tab)
Leveraging Time-of-Check and Time-of-Use (TOCTOU) Race Conditions (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 30 Jan 2026, 10:02 UTC

WeaknessesCWE-367

Technical details

References

Community reviews

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