EUVD-2026-83925Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessGain local unprivileged access
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DeliveryReplace clean-target parent dir with junction + symlink
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ExploitTrigger elevated BleachBit cleaning
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ExecutionRedirect deletion to attacker-chosen system file
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PersistAbuse Windows Installer rollback
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ImpactObtain local SYSTEM
Vulnerability Assessment
| Weakness |
CWE
ASVS 5.0
V15 - Secure Coding and Architecture TOCTOU prevention
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| Exploitation Conditions | Requires an interactive, authenticated but unprivileged local Windows user, and BleachBit prior to 6.0.1 being run with elevated/privileged rights during a cleaning operation (privileged Windows cleaning mode). The attacker must win a TOCTOU race by replacing the clean target's parent directory with a Windows junction and placing a native symlink before the elevated deletion occurs. Exploitation is limited to Windows (junction/symlink mechanics), needs local access (not remotely reachable), and depends on BleachBit performing a privileged clean; the SYSTEM-escalation step additionally leverages Windows Installer rollback behavior. |
| Impact | This is a genuine local privilege-escalation issue worth prioritizing on Windows hosts that run BleachBit with elevation. The CVSS 3.1 vector (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H = 7.8 HIGH) is internally consistent with the description: a local, low-privileged user exploits a TOCTOU race (CWE-367) in privileged Windows cleaning to redirect an elevated deletion, chaining to SYSTEM. No EPSS score, KEV listing, POC, or SSVC data was provided in the intelligence, so exploitation likelihood must be judged on structure alone rather than observed activity. The AC:L rating is slightly optimistic for a race condition, but junction/symlink swaps against a predictable clean target are reliably winnable (plant-then-trigger), so AC:L is defensible. The main limiting factor is that this is not remotely reachable and requires an already-authenticated local user plus BleachBit being run with privilege - so it is an escalation primitive, not an initial-access vector. One data caveat: the input Tags label this 'Information Disclosure,' which conflicts with the actual mechanism (arbitrary file deletion → SYSTEM), and 'Microsoft' is listed as a tag although BleachBit is an independent open-source project, not a Microsoft product. |
| Exploit ScenarioDerived | A logged-in unprivileged Windows user replaces the parent directory of a file BleachBit is about to clean with a junction, and plants a native symlink so that when the elevated BleachBit process deletes the 'target,' it actually deletes an attacker-chosen system file. The attacker combines this arbitrary privileged file deletion with Windows Installer rollback behavior to obtain a SYSTEM shell. No public POC is referenced in the provided intelligence, though the vendor security advisory (GHSA-vcjw-px28-5w94) and fix commit describe the flaw in detail. |
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Alert meAnalysisAIv1 – Sep 21, 2026
Local privilege escalation in BleachBit on Windows lets an unprivileged local user turn an elevated cleaning operation into arbitrary privileged file deletion and, via Windows Installer rollback behavior, full SYSTEM privileges. The flaw affects BleachBit versions prior to 6.0.1 and is exploitable by an authenticated, unprivileged interactive user who wins a TOCTOU race while BleachBit runs with elevated rights in privileged Windows cleaning mode; the vector is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H (7.8). No public exploit code was identified and there is no CISA KEV listing at time of analysis, so the practical risk is a genuine local privilege-escalation issue worth prioritizing on Windows hosts that run BleachBit with elevation.
RemediationAI
Upgrade to BleachBit 6.0.1 or later, which is the vendor-released fix: the release at https://github.com/bleachbit/bleachbit/releases/tag/v6.0.1 incorporates PR https://github.com/bleachbit/bleachbit/pull/1774 and commit https://github.com/bleachbit/bleachbit/commit/ee128238e92c7192f0c4d6406b1bd0cd9155e7e0, and the security advisory is at https://github.com/bleachbit/bleachbit/security/advisories/GHSA-vcjw-px28-5w94. If upgrading immediately is not possible on affected Windows hosts, stop running cleans in privileged/elevated mode (only run BleachBit as a normal, non-elevated user) - this removes the arbitrary privileged file deletion primitive entirely, at the cost of no longer cleaning system-wide locations that require elevation. As an additional compensating control, restrict which local accounts can trigger or schedule elevated BleachBit cleaning jobs, since exploitation requires an interactive, authenticated but unprivileged local user to race the delete; this narrows the attacker pool but does not eliminate the TOCTOU if any untrusted local user can invoke an elevated clean. Note that hardening directory ACLs or disabling reparse points in the cleaned paths may reduce exposure but is fragile and location-specific, so patching to 6.0.1 remains the primary and recommended fix.
Affected VersionsENISA
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 1 package in euvd
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Technical ContextAI · show details
The root cause is a time-of-check-to-time-of-use (TOCTOU) race, classified as CWE-367, in BleachBit's privileged Windows cleaning path. Before deleting a target file, BleachBit does not lock and validate the target's parent directory, so between the check and the actual deletion an attacker who controls the directory tree can swap the parent directory for a Windows junction and introduce a native symlink, redirecting the elevated delete operation to an attacker-chosen file anywhere the privileged process can reach. The upstream fix (PR #1774, commit ee128238e92c7192f0c4d6406b1bd0cd9155e7e0, released in v6.0.1) adds a delete_file() helper that opens a handle to the resolved parent directory with CreateFile using GENERIC_READ, FILE_SHARE_READ and FILE_FLAG_BACKUP_SEMANTICS before calling the actual removal, keeping a lock on the parent so it cannot be reparse-point-swapped mid-operation. The elevated deletion primitive is then chained with documented Windows Installer self-repair/rollback behavior to escalate the attacker from a low-privileged local account to SYSTEM. Exploitation is confined to Windows because it depends on NTFS junction and native symlink mechanics; the CVSS vector confirms local access (AV:L) and low privileges (PR:L) with no user interaction (UI:N), while scope remains unchanged (S:U).
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Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Local authenticated unprivileged user (AV:L/PR:L); the plant-then-trigger junction/symlink swap is reliably winnable so AC:L; arbitrary deletion escalates to SYSTEM giving full C/I/A:H.
Primary rating from Vendor (GitHub_M).
CVSS VectorVendor: GitHub_M
Lifecycle Timeline
2DescriptionCVE.org
BleachBit cleans files to free disk space and to maintain privacy. Prior to 6.0.1, privileged Windows cleaning does not lock and validate a target's parent directory before deletion. A local unprivileged user can replace that directory with a Windows junction and use a native symlink to redirect the elevated deletion to an attacker-selected file. The arbitrary privileged file deletion can be combined with Windows Installer behavior to obtain local SYSTEM privileges. This issue is fixed in version 6.0.1.
Technical POC Analysis
Advisory: GHSA-vcjw-px28-5w94.
Full technical POC analysis - root cause, step-by-step exploitation and patch breakdown - is part of the Pro and Business plans.
Executive ViewAI
A privilege-escalation flaw in BleachBit, a widely used system-cleaning utility, allows an ordinary user on a Windows workstation or server to gain full SYSTEM-level control of that machine. Because the attack is local, the exposure is limited to hosts where BleachBit is installed and run with administrator rights - typically IT, engineering, or power-user endpoints rather than the entire fleet. Leadership should care because a single low-privilege user account, or an attacker who has already landed on such a host, could escalate to full administrative control, undermining endpoint hardening and widening the blast radius of any initial compromise. No public exploit code or active exploitation has been observed, so this is a prioritize-and-patch item rather than an emergency.
Apply vendor patch.
Threat Intelligence Overview
NVD
CVE.org
EPSS
Vulnrichment
GitHub
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
Exploit-DB