CVE-2026-102740
Description
A flaw was found in AsyncHttpClient. Resumable download state is stored in a predictable shared temporary directory with insecure permissions and link-following file operations. A local attacker can exploit this issue by placing a symbolic link in the shared location to overwrite arbitrary files writable by the application process, or by reading the state file to obtain sensitive download URLs and authentication tokens.
Statement
This vulnerability is rated as Moderate impact for Red Hat products because exploitation requires existing local access to the system and is constrained to configurations utilizing resumable download handlers. In typical enterprise deployments, applications bundling AsyncHttpClient run under dedicated service accounts within isolated containers or restricted host environments, significantly limiting exposure to unprivileged local actors. Successful exploitation could allow a local adversary on multi-user systems to expose session tokens in download paths or overwrite files accessible to the application process.
Mitigation
Avoid using ResumableAsyncHandler on hosts with shared temp directories, or point the ahc resumable store at a private directory (upstream workaround from GHSA-cf59-3jcr-vfhw).
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 | 5.8 | N/A | 5.8 |
| Attack Vector | Local | N/A | Local |
| Attack Complexity | High | N/A | High |
| Privileges Required | Low | N/A | Low |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | Low | N/A | Low |
| Integrity Impact | High | N/A | High |
| Availability Impact | Low | N/A | Low |
Vector
Red Hat: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:H/A:L
cve.org: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:H/A:L
Understanding the Weakness (CWE)
Confidentiality,Integrity,Access Control
Technical Impact: Read Files or Directories; Modify Files or Directories; Bypass Protection Mechanism
An attacker may be able to traverse the file system to unintended locations and read or overwrite the contents of unexpected files. If the files are used for a security mechanism then an attacker may be able to bypass the mechanism.
Other
Technical Impact: Execute Unauthorized Code or Commands
Windows simple shortcuts, sometimes referred to as soft links, can be exploited remotely since a ".LNK" file can be uploaded like a normal file. This can enable remote execution.
Frequently Asked Questions
Not sure what something means? Check out our Security Glossary.
Want to get errata notifications? Sign up here.
