CVE-2026-73282
Description
A flaw was found in OpenSSH. A use-after-free vulnerability exists in the ssh client when handling concurrent remote-forwarding operations. This can occur if a remote forwarding is added via the local session multiplexing socket while a remote forwarding open request is pending with the server. A remote attacker with high attack complexity could potentially exploit this to achieve low impact on confidentiality and integrity.
Statement
A use-after-free flaw exists in OpenSSH's ssh client during concurrent remote-forwarding processing. When adding a remote forward via the local session multiplexing socket while a server remote-forward open request is pending, realloc data management fails, freeing memory that remains actively referenced. A remote attacker with high attack complexity can exploit this timing window to corrupt process memory, posing a low impact to confidentiality, integrity, and availability.
Mitigation
Avoid issuing dynamic remote-forwarding commands over active SSH multiplexing connections, or disable socket multiplexing by setting ControlMaster no in ~/.ssh/config.
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 | 5.6 | N/A | 4.8 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | High | N/A | High |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | Low | N/A | Low |
| Integrity Impact | Low | N/A | Low |
| Availability Impact | Low | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L
cve.org: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
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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