CVE-2026-46300
Description
A flaw was found in the Linux kernel's XFRM ESP-in-TCP subsystem. Unsafe in-place cryptographic processing allows a low-privileged local attacker to write arbitrary bytes into the page cache of read-only files, including sensitive system files. An attacker can exploit this to overwrite privileged binaries and gain root privileges.
Security Bulletin
Statement
This issue is classified as Important, rather than Critical severity, because exploitation requires local access to the system. A low-privileged local attacker can exploit this flaw in the Linux kernel's XFRM ESP-in-TCP subsystem to gain root privileges by overwriting sensitive system files. Exploitation does not require user interaction, potentially resulting in full compromise of confidentiality, integrity, and availability.
Mitigation
See the security bulletin for a detailed mitigation procedure.
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 | 7.8 | 7.8 | 7.8 |
| Attack Vector | Local | Local | Local |
| Attack Complexity | Low | Low | Low |
| Privileges Required | Low | Low | Low |
| User Interaction | None | None | None |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | High | High | High |
| Integrity Impact | High | High | High |
| Availability Impact | High | High | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD: CVSS:3.1/AV:L/AC:L/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,Confidentiality,Availability,Access Control
Technical Impact: Modify Memory; Execute Unauthorized Code or Commands; Gain Privileges or Assume Identity; DoS: Crash, Exit, or Restart; Bypass Protection Mechanism
Clearly, write-what-where conditions can be used to write data to areas of memory outside the scope of a policy. Also, they almost invariably can be used to execute arbitrary code, which is usually outside the scope of a program's implicit security policy. If the attacker can overwrite a pointer's worth of memory (usually 32 or 64 bits), they can redirect a function pointer to their own malicious code. Even when the attacker can only modify a single byte arbitrary code execution can be possible. Sometimes this is because the same problem can be exploited repeatedly to the same effect. Other times it is because the attacker can overwrite security-critical application-specific data -- such as a flag indicating whether the user is an administrator.
Integrity,Availability
Technical Impact: DoS: Crash, Exit, or Restart; Modify Memory
Many memory accesses can lead to program termination, such as when writing to addresses that are invalid for the current process.
Access Control,Other
Technical Impact: Bypass Protection Mechanism; Other
When the consequence is arbitrary code execution, this can often be used to subvert any other security service.
Frequently Asked Questions
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