Red Hat Enterprise Linux 10: Time-of-check Time-of-use (TOCTOU) Race Condition
CVE-2026-78410 is a high-severity time-of-check time-of-use (TOCTOU) race condition vulnerability in Red Hat Enterprise Linux 10 from Red Hat, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. There is no confirmed exploitation so far. EPSS estimates a 0.2% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of Red Hat Enterprise Linux 10 you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on github.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Red Hat | Red Hat Enterprise Linux 10 | Not specified in the record | Not stated |
| Red Hat | Red Hat Cost Management On-Premise 1 | Not specified in the record | Not stated |
| Red Hat | Red Hat Hardened Images | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 7 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 8 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 9 | Not specified in the record | Not stated |
| Red Hat | Red Hat OpenShift Container Platform 4 | Not specified in the record | Not stated |
| Red Hat | Red Hat OpenShift Container Platform 5 | Not specified in the record | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by CNA (redhat.com).
Official description
A flaw was found in util-linux. Restricted bind mounts take the source path from fstab but do not pin that source before the privileged mount. A local unprivileged user who can replace the authorized source or a writable ancestor can redirect SUID mount(8) to bind another host directory. If the fstab entry also sets X-mount.owner, X-mount.group, or X-mount.mode, root then changes ownership or mode on that redirected inode.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: 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 developers prevent this class of flaw
- 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.
- 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.
- Limit the interleaving of operations on files from multiple processes.
More Time-of-check Time-of-use (TOCTOU) Race Condition vulnerabilities (CWE-367)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other references
Other vulnerabilities in Red Hat Enterprise Linux 10
- 8.8 High severity
- 7.5 High severity
- 7.5 High severity
- 7.9 High severity
- 7.3 High severity
- 7.5 High severity
Recent Time-of-check Time-of-use (TOCTOU) Race Condition vulnerabilities
- 7.5 High severity
- 9.3 Critical severity
- 7.3 High severity
- 8.1 High severity
- 7.8 High severity
- 8.1 High severity
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