EUVD-2026-25024
GHSA-4wrp-79m8-9m9p
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessGain local shell access
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DeliveryMonitor split execution or predict via cron
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ExploitPrepare symbolic link in target directory
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ExecutionReplace output path with symlink during TOCTOU window
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Persistsplit truncates symlink target
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ImpactData loss on sensitive file
Vulnerability Assessment
| Weakness |
CWE
ASVS 5.0
V15 - Secure Coding and Architecture TOCTOU prevention
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| Exploitation Conditions | Attack requires: (1) local user account with shell access to the target system, (2) write permissions to the directory containing the split output file or control over intermediate path components, (3) ability to detect or predict when split will execute (via cron, manual invocation, monitoring), (4) precise timing to swap the output path with a symbolic link between the path validation check and the file open with truncation. Default installations do not inherently prevent this - it depends on local access controls. The vulnerability does NOT affect remote attackers or unauthenticated access. It is MITIGATED if the output directory is owned exclusively by the user running split and other local users cannot write to it. |
| Impact | CVSS 6.3 reflects local-only attack vector (AV:L), high attack complexity (AC:H - requires precise timing and directory write access), low privilege (PR:L - local user account), no confidentiality impact (C:N), high integrity and availability impact (I:H/A:H). SSVC assessment states exploitation as 'none' (no public weaponized exploits), automatable as 'no' (manual timing required to win race), technical impact as 'partial' (data loss is significant but scoped to files the attacker can already access). The contradiction between CVSS integrity/availability ratings (high) and SSVC technical impact (partial) reflects SSVC's narrower scope: SSVC only counts impacts beyond what the attacker can already do locally. Real-world risk is moderate - requires local access, precise timing, and knowledge of target paths, but data loss impact is severe for affected organizations. This is NOT a high-priority network-facing risk but represents real local privilege escalation in multi-user systems. |
| Exploit ScenarioDerived | A local user on a shared system runs split to process a file in /tmp. An attacker with write access to /tmp uses inotify or polling to detect the split process, then rapidly replaces the output file path with a symbolic link pointing to the user's SSH private key. The split process's TOCTOU window allows the truncation to follow the link, destroying the private key and causing service disruption or account compromise. |
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Alert meAnalysisAIv1 – Apr 23, 2026
The split utility in uutils coreutils contains a time-of-check to time-of-use (TOCTOU) race condition that allows local attackers with directory write access to manipulate symbolic links between the initial path validation and file truncation, causing data loss to unintended target files including the input file or other sensitive files. CVSS 6.3 (local, high complexity, low privilege required); SSVC assesses as non-exploitable in automated attacks but partial technical impact due to manual race window exploitation requirements.
RemediationAI
Vendor-released patch available via GitHub pull request https://github.com/uutils/coreutils/pull/11401. Update uutils coreutils to the patched version as soon as it is released. As immediate compensating control for multi-user systems where local attackers exist, disable split command execution for untrusted users via Unix access controls (chmod, sudo rules), or restrict write permissions to directories where split might be executed. This introduces usability trade-offs in shared systems. No functional workaround exists short of these access controls, as the root cause requires fixing the underlying TOCTOU logic to perform atomic validation-and-open operations or use file descriptor-based operations that prevent symbolic link traversal between checks.
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 1 package in cargo
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Technical ContextAI · show details
The vulnerability stems from CWE-367 (improper restriction of rendered UI layers or frames), manifesting as a TOCTOU race condition in file path validation. The split utility first validates that input and output file paths differ using string comparison, then later opens the output file with truncation flags. This two-step process creates a window where a local attacker with write permissions to the target directory can swap a non-symbolic-link path with a symbolic link pointing to a sensitive file (input file, system configuration, user data). The path-based check passes because the symbolic link itself differs from the input path, but the subsequent open() call with O_TRUNC follows the link and truncates the link target. CPE indicates all versions of uutils coreutils are affected.
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Severity by source
AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:H
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
Lifecycle Timeline
2DescriptionCVE.org
A Time-of-Check to Time-of-Use (TOCTOU) vulnerability exists in the split utility of uutils coreutils. The program attempts to prevent data loss by checking for identity between input and output files using their file paths before initiating the split operation. However, the utility subsequently opens the output file with truncation after this path-based validation is complete. A local attacker with write access to the directory can exploit this race window by manipulating mutable path components (e.g., swapping a path with a symbolic link). This can cause split to truncate and write to an unintended target file, potentially including the input file itself or other sensitive files accessible to the process, leading to permanent data loss.
Threat Intelligence Overview
NVD
CVE.org
EPSS
Vulnrichment
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.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.
Affected Products (CPE)CVE.org
The parse_datetime function in GNU coreutils allows remote attackers to cause a denial of service (crash) or possibly ex
Privilege escalation to root in uutils coreutils chroot utility allows low-privileged local attackers with write access
Local privilege escalation in uutils coreutils before 0.10.0: the `install` utility applies a requested setuid/setgid mo
Recursive chmod operations can bypass --preserve-root protection in uutils coreutils versions prior to 0.6.0, allowing l
Local privilege escalation in uutils coreutils mkfifo allows authenticated users to downgrade permissions on arbitrary f
Privilege escalation in uutils coreutils mkfifo utility allows local attackers with low privileges to manipulate file pe
Bypass of --preserve-root protection in uutils coreutils rm utility allows local users to recursively delete the root fi
The mv utility in uutils coreutils improperly expands symbolic links instead of preserving them during moves across file
The cp utility in uutils coreutils improperly preserves setuid and setgid bits when the chown operation fails during fil
A time-of-check to time-of-use (TOCTOU) race condition in the mv utility of uutils coreutils during cross-device move op
The touch utility in uutils coreutils suffers from a Time-of-Check to Time-of-Use (TOCTOU) race condition that allows lo
Privilege escalation via symlink attack in uutils coreutils install utility when using the -D flag allows local attacker
Exploit-DB