CVE-2026-89607
Description
A flaw was found in ecryptfs in the Linux kernel. The parse_tag_3_packet() function does not properly validate the size of the encrypted key, allowing an oversized key to be processed. This improper validation leads to out-of-bounds writes, corrupting critical data structures within the ecryptfs_auth_tok and ecryptfs_crypt_stat structs. A local attacker could potentially exploit this memory corruption to achieve privilege escalation or cause a denial of service.
Statement
Red Hat has classified this vulnerability as having an Important impact because successful exploitation by an authenticated local user can trigger kernel memory corruption, potentially granting elevated privileges or crashing the system. The issue exists within the eCryptfs cryptographic filesystem subsystem during the handling of passphrase authentication tokens with specific cipher configurations. Exposure across standard enterprise deployments is significantly reduced because eCryptfs is not enabled in default Red Hat Enterprise Linux kernels. Exploitation requires an environment where eCryptfs is active and local unprivileged users can present crafted filesystem metadata.
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).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7 | N/A | 7.8 |
| Attack Vector | Local | N/A | Local |
| Attack Complexity | High | N/A | Low |
| Privileges Required | Low | N/A | Low |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | High | N/A | High |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
cve.org: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Integrity
Technical Impact: Modify Memory; Execute Unauthorized Code or Commands
Write operations could cause memory corruption. In some cases, an adversary can modify control data such as return addresses in order to execute unexpected code.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
Attempting to access out-of-range, invalid, or unauthorized memory could cause the product to crash.
Other
Technical Impact: Unexpected State
Subsequent write operations can produce undefined or unexpected results.
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