CVE-2025-52881
Description
A flaw was found in runc. This attack is a more sophisticated variant of CVE-2019-16884, which was a flaw that allowed an attacker to trick runc into writing the LSM process labels for a container process into a dummy tmpfs file and thus not apply the correct LSM labels to the container process. The mitigation applied for CVE-2019-16884 was fairly limited and effectively only caused runc to verify that when we write LSM labels that those labels are actual procfs files.
Statement
Red Hat considers this as an Important flaw since the impact is limited to local attack with minimal privileges in order to jeopardize the environment.
Mitigation
Potential mitigations for this issue include:
* Using rootless containers, as doing so will block most of the inadvertent writes (runc would run with reduced privileges, making attempts to write to procfs files ineffective).
* Based on our analysis, neither AppArmor or SELinux can protect against the full version of the redirected write attack. The container runtime is generally privileged enough to write to arbitrary procfs files, which is more than sufficient to cause a container breakout.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 8.2 | 7.5 | N/A |
| Attack Vector | Local | Local | N/A |
| Attack Complexity | Low | High | N/A |
| Privileges Required | Low | Low | N/A |
| User Interaction | Required | Required | N/A |
| Scope | Changed | Changed | N/A |
| Confidentiality | High | High | N/A |
| Integrity Impact | High | High | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H
NVD: CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:H
Understanding the Weakness (CWE)
Confidentiality,Integrity,Access Control
Technical Impact: Read Files or Directories; Modify Files or Directories; Bypass Protection Mechanism
An attacker may be able to traverse the file system to unintended locations and read or overwrite the contents of unexpected files. If the files are used for a security mechanism then an attacker may be able to bypass the mechanism.
Other
Technical Impact: Execute Unauthorized Code or Commands
Windows simple shortcuts, sometimes referred to as soft links, can be exploited remotely since a ".LNK" file can be uploaded like a normal file. This can enable remote execution.
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