GHSA-9gh9-hwpr-rvqq CVE-2026-35352
uutils coreutils has a Time-of-Check to Time-of-Use (TOCTOU) race condition
- Severity
- 7.0 / 10
- High · CVSS 3.1
- Exploit chance (EPSS)
- 0.15%
- Chance of exploitation in the next 30 days. Higher than 3.91% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition
- Fix
- None yet
- No fixed version published
Description
A Time-of-Check to Time-of-Use (TOCTOU) race condition exists in the mkfifo utility of uutils coreutils. The utility creates a FIFO and then performs a path-based chmod to set permissions. A local attacker with write access to the parent directory can swap the newly created FIFO for a symbolic link between these two operations. This redirects the chmod call to an arbitrary file, potentially enabling privilege escalation if the utility is run with elevated privileges.
Affected versions
crates.io
| Package | Vulnerable | Fixed in |
|---|---|---|
| coreutils | <= 0.8.0 |
No fix yet |
How to fix
No fixed version has been published yet. Until one is, remove or replace the package, or turn off or isolate the affected feature. This page updates when a fix ships.
Severity breakdown
CVSS 3.1 7.0
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
- Attack vector
- Local
- Attack complexity
- High
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Weakness
CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition
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.
How to prevent it
- 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.
- Implementation, Architecture and Design: If you cannot perform operations atomically and you must share access to the resource between multiple processes or threads, then try to limit the amount of time (CPU cycles) between the check and use of the resource. This will not fix the problem, but it could make it more difficult for an attack to succeed.
- Implementation: Recheck the resource after the use call to verify that the action was taken appropriately.
- Architecture and Design: Ensure that some environmental locking mechanism can be used to protect resources effectively.
- Implementation: Ensure that locking occurs before the check, as opposed to afterwards, such that the resource, as checked, is the same as it is when in use.
References
Advisories
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-m2pg-c7m6-77pj uutils coreutils has an Improper Input Validation Issue in its cut Utility | Medium | Also affects coreutils |
| GHSA-fhr3-xh3q-69w6 uutils coreutils has an Incorrect Provision of Specified Functionality Issue | Low | Also affects coreutils |
| GHSA-5pv5-xh52-hvrp uutils coreutils has an Incorrect Short Circuit Evaluation Issue | Low | Also affects coreutils |
| GHSA-5v4g-vw9x-h534 uutils coreutils has an Improper Input Validation Issue in its env Utility | Low | Also affects coreutils |
| GHSA-6g8r-74qp-6859 uutils coreutils has a Time-of-check Time-of-use (TOCTOU) Race Condition | Medium | Also affects coreutils |
| GHSA-vx9m-xjwf-8cqm uutils coreutils has an Improper Handling of Unicode Encoding Issue | Low | Also affects coreutils |
| GHSA-4wrp-79m8-9m9p uutils coreutils has a Time-of-check Time-of-use (TOCTOU) Race Condition | Medium | Also affects coreutils |
| GHSA-wq63-vh5h-pr5p uutils coreutils has a UNIX Symbolic Link (Symlink) Following issue | Medium | Also affects coreutils |
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