CVE-2026-3805
Description
A flaw was found in curl. When handling a second Server Message Block (SMB) request to the same host, curl incorrectly accesses memory that has already been freed. This memory corruption vulnerability, known as a use-after-free, could allow a remote attacker to potentially execute arbitrary code or cause a denial of service.
Statement
This Moderate flaw in curl's handling of Server Message Block (SMB) connections can lead to a use-after-free vulnerability. When a second SMB request is made to the same host, curl may incorrectly access previously freed memory, potentially resulting in arbitrary code execution or a denial of service. However, successful exploitation is considered difficult due to the specific conditions required to trigger the flaw reliably.
Mitigation
To mitigate this issue, avoid using curl for Server Message Block (SMB) transfers. This can be achieved by ensuring that applications utilizing curl do not initiate SMB requests. If SMB transfers are essential, consider isolating the affected systems or restricting network access to SMB services. A service restart or reload may be required for changes to take effect.
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 | 6.3 | N/A | 7.5 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | Required | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | Low | N/A | None |
| Integrity Impact | Low | N/A | None |
| Availability Impact | Low | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory
If the expired pointer is used in a read operation, an attacker might be able to control data read in by the application.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
If the expired pointer references a memory location that is not accessible to the product, or points to a location that is "malformed" (such as NULL) or larger than expected by a read or write operation, then a crash may occur.
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands
If the expired pointer is used in a function call, or points to unexpected data in a write operation, then code execution may be possible.
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