CVE-2026-0861
Description
A flaw was found in the glibc library. Passing an excessively large alignment value to the memalign suite of functions, such as memalign, posix_memalign, aligned_alloc, valloc and pvalloc, an integer overflow can occur during internal size calculations due to improper overflow checks, causing an allocation of a small chunk of memory which is subsequently used for writing. This issue can result in an application crash or heap memory corruption.
Statement
To exploit this flaw, an attacker needs to find an application linked to the glibc library that is using one of the vulnerable functions (memalign, posix_memalign, aligned_alloc, valloc or pvalloc) in a way that the alignment parameter can be user-controlled, allowing an attacker to trigger the integer overflow. However, the alignment parameter used by the functions is usually hard-coded power of two and do not allow arbitrary values, specially values supplied by a user. There is no known application vulnerable to this issue.
Also, default Red Hat Enterprise Linux security features, including SELinux enforcement, Address Space Layout Randomization (ASLR) and memory protections significantly increase the difficult of achieving arbitrary code execution, limiting the impact of this vulnerability.
Due to these reasons, this vulnerability has been rated with a low severity.
Mitigation
Applications calling one of the vulnerable functions and allowing the alignment parameter to be set by user-controlled input can implement additional validations checks, ensuring the alignment value is a power of two and does not exceed a sane limit, for example the system page size or a maximum of 64KB. This prevents the excessively large value required to trigger the integer overflow.
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 | 8.1 | N/A | 8.4 |
| Attack Vector | Network | N/A | Local |
| Attack Complexity | High | N/A | Low |
| Privileges Required | None | N/A | None |
| 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:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
cve.org: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart; DoS: Resource Consumption (Memory); DoS: Instability
This weakness can generally lead to undefined behavior and therefore crashes. When the calculated result is used for resource allocation, this weakness can cause too many (or too few) resources to be allocated, possibly enabling crashes if the product requests more resources than can be provided.
Integrity
Technical Impact: Modify Memory
If the value in question is important to data (as opposed to flow), simple data corruption has occurred. Also, if the overflow/wraparound results in other conditions such as buffer overflows, further memory corruption may occur.
Confidentiality,Availability,Access Control
Technical Impact: Execute Unauthorized Code or Commands; Bypass Protection Mechanism
This weakness can sometimes trigger buffer overflows, which can be used to execute arbitrary code. This is usually outside the scope of the product's implicit security policy.
Availability,Other
Technical Impact: Alter Execution Logic; DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU)
If the overflow/wraparound occurs in a loop index variable, this could cause the loop to terminate at the wrong time - too early, too late, or not at all (i.e., infinite loops). With too many iterations, some loops could consume too many resources such as memory, file handles, etc., possibly leading to a crash or other DoS.
Access Control
Technical Impact: Bypass Protection Mechanism
If integer values are used in security-critical decisions, such as calculating quotas or allocation limits, integer overflows can be used to cause an incorrect security decision.
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