CVE-2026-82327
Description
A flaw was found in libsolv, a dependency-resolution library used by RPM-based package managers such as dnf and zypper to work with .solv repository cache files. When libsolv rewrites a .solv cache file, it reads directory-id values from the file's compressed filelist data without validating that they fall within the expected range. A corrupted or specially crafted .solv cache file (for example, one left in a torn state after an unclean system shutdown) can cause an out-of-bounds memory write when a tool such as dnf, yum, or zypper next processes it. Successful exploitation is expected to result in a crash of the affected tool (denial of service); it is not expected to allow arbitrary code execution because the out-of-bounds write always stores a fixed, non-attacker-controlled value.
Statement
The vulnerable code path is the vertical/paged (lazily loaded) filelist decoder used by repo_write(), reached only when a consumer (e.g. dnf/libdnf) rewrites a .solv cache after having loaded one containing SOLVABLE_FILELIST data stored with KEY_STORAGE_VERTICAL_OFFSET. The out-of-bounds write always stores a fixed, non-attacker-controlled value, resulting in a crash (denial of service) rather than a confidentiality or integrity compromise.
Mitigation
No mitigation is currently available that meets Red Hat Product Security's standards for usability, deployment, applicability, 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).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.5 | N/A | 5.5 |
| Attack Vector | Local | N/A | Local |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | Required | N/A | Required |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | None |
| Integrity Impact | None | N/A | None |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Red Hat CVSS v3 Score Explanation
Independent assessment: local, low-complexity trigger via a corrupted or crafted .solv cache file that a victim tool (dnf/yum/zypper/dumpsolv) must open; no privileges needed by the attacker but the victim must be induced to process the file; the primitive is an OOB write of a fixed constant (1) at an offset derived from an unvalidated id, which in practice manifests as a crash (availability impact) rather than confidentiality/integrity compromise, since the written value is not attacker-controlled data.
Understanding the Weakness (CWE)
Integrity,Availability
Technical Impact: DoS: Crash, Exit, or Restart
Use of an index that is outside the bounds of an array will very likely result in the corruption of relevant memory and perhaps instructions, leading to a crash, if the values are outside of the valid memory area.
Integrity
Technical Impact: Modify Memory
If the memory corrupted is data, rather than instructions, the system will continue to function with improper values.
Confidentiality,Integrity
Technical Impact: Modify Memory; Read Memory
Use of an index that is outside the bounds of an array can also trigger out-of-bounds read or write operations, or operations on the wrong objects; i.e., "buffer overflows" are not always the result. This may result in the exposure or modification of sensitive data.
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands
If the memory accessible by the attacker can be effectively controlled, it may be possible to execute arbitrary code, as with a standard buffer overflow and possibly without the use of large inputs if a precise index can be controlled.
Integrity,Availability,Confidentiality
Technical Impact: DoS: Crash, Exit, or Restart; Execute Unauthorized Code or Commands; Read Memory; Modify Memory
A single fault could allow either an overflow (CWE-788) or underflow (CWE-786) of the array index. What happens next will depend on the type of operation being performed out of bounds, but can expose sensitive information, cause a system crash, or possibly lead to arbitrary code execution.
Acknowledgements
Red Hat would like to thank Dinko Georgiev (StorPool) for reporting this issue.
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