CVE-2025-7425
Description
A flaw was found in libxslt where the attribute type, atype, flags are modified in a way that corrupts internal memory management. When XSLT functions, such as the key() process, result in tree fragments, this corruption prevents the proper cleanup of ID attributes. As a result, the system may access freed memory, causing crashes or enabling attackers to trigger heap corruption.
Statement
This heap-use-after-free vulnerability in libxslt is rated Important because it can lead to memory corruption and application crashes. The flaw arises when internal attribute metadata (atype) is modified by libxslt's xsltSetSourceNodeFlags() function during processing of result tree fragments. If the flag corruption prevents proper removal of ID references, later memory cleanup routines may operate on already-freed memory. Since libxslt is commonly used in server-side XML processing, this could result in denial-of-service or potentially facilitate code execution under certain memory reuse conditions.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
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 | N/A | 7.8 |
| Attack Vector | Local | N/A | Local |
| Attack Complexity | High | N/A | High |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Changed | N/A | Changed |
| Confidentiality | None | N/A | None |
| Integrity Impact | High | N/A | High |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:H
cve.org: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:H
Understanding the Weakness (CWE)
Integrity
Technical Impact: Modify Memory
The use of previously freed memory may corrupt valid data, if the memory area in question has been allocated and used properly elsewhere.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
If chunk consolidation occurs after the use of previously freed data, the process may crash when invalid data is used as chunk information.
Confidentiality
Technical Impact: Read Memory
Read operations on freed memory can sometimes leak sensitive information instead of causing a crash
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands
If malicious data is entered before chunk consolidation can take place, it may be possible to take advantage of a write-what-where primitive to execute arbitrary code. If the newly allocated data happens to hold a class, in C++ for example, various function pointers may be scattered within the heap data. If one of these function pointers is overwritten with an address to valid shellcode, execution of arbitrary code can be achieved.
Acknowledgements
Red Hat would like to thank Sergei Glazunov (Google Project Zero) for reporting this issue.
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