Red Hat Enterprise Linux 10: Improper Link Resolution Before File Access
CVE-2026-87766 is a high-severity improper link resolution before file access vulnerability in Red Hat Enterprise Linux 10 from Red Hat, with a CVSS 3.1 base score of 8.8 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 0.21% 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
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
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- 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:C/C:H/I:H/A:H. Scored by CNA (redhat.com).
Official description
A flaw was found in bubblewrap. During sandbox setup, creating files or directories under the new root can follow a parent symlink onto the host via /oldroot, writing attacker-chosen paths outside the sandbox as the launching user. This happens before the sandboxed process starts. This issue is GHSA-pxhw-h44j-8pfx. It is fixed in bubblewrap 0.12.0.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Link Resolution Before File Access
The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.
How developers prevent this class of flaw
- Follow the principle of least privilege when assigning access rights to entities in a software system. Denying access to a file can prevent an attacker from replacing that file with a link to a sensitive file. Ensure good compartmentalization in the system to provide protected areas that can be trusted.
More Improper Link Resolution Before File Access vulnerabilities (CWE-59)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Other references
- access.redhat.com/errata/RHSA-2026:85306
- access.redhat.com/errata/RHSA-2026:85308
- access.redhat.com/errata/RHSA-2026:85309
- access.redhat.com/errata/RHSA-2026:85312
- access.redhat.com/errata/RHSA-2026:85313
- access.redhat.com/errata/RHSA-2026:85317
- access.redhat.com/errata/RHSA-2026:85319
- access.redhat.com/errata/RHSA-2026:85322
- access.redhat.com/errata/RHSA-2026:85324
- access.redhat.com/errata/RHSA-2026:85325
- access.redhat.com/errata/RHSA-2026:98521
- access.redhat.com/security/cve/CVE-2026-87766
- bugs.debian.org/1145655
- bugzilla.redhat.com/show_bug.cgi?id=2530542
- openwall.com/lists/oss-security/2026/08/27/7
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 Improper Link Resolution Before File Access vulnerabilities
- 7.0 High severity
- 7.8 High severity
Microsoft Windows Link Following Exploited
- 7.8 High severity
- 7.0 High severity
- 7.1 High severity
- 7.8 High severity
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