Vulnerability · Published Oct 15, 2026 · Assigned by GitHub_M
CVE-2026-102740AsyncHttpClient: Resumable download index store is created world-readable and follows a planted symlink
Medium 5.8
In plain English
A medium-severity incorrect permission assignment in async-http-client from AsyncHttpClient. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 1% of all known vulnerabilities).
Official description
The AsyncHttpClient library allows Java applications to execute HTTP requests and asynchronously process HTTP responses. From 2.0.0 until 2.16.1 and 3.0.12, PropertiesBasedResumableProcessor stores resumable download state at the predictable shared path $java.io.tmpdir/ahc/ResumableAsyncHandler.properties with default permissions and link-following file operations. A local user who can read the shared store can see download URLs, including embedded user information or query tokens. A local user who can write within or pre-create the affected shared store directory can plant a symbolic link that the client follows when saving state, truncating and overwriting a target file writable by the client process. The filesystem path is used when ResumableAsyncHandler decorates another AsyncHandler, while the no-argument constructors use a no-op processor and are unaffected. This issue is fixed in versions 2.16.1 and 3.0.12.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | async-http-client | no fix listed | DEBIAN-CVE-2026-102740 |
| Ubuntu:22.04:LTS | async-http-client | no fix listed | UBUNTU-CVE-2026-102740 |
| Ubuntu:24.04:LTS | async-http-client | no fix listed | UBUNTU-CVE-2026-102740 |
| Ubuntu:26.04:LTS | async-http-client | no fix listed | UBUNTU-CVE-2026-102740 |
| Ubuntu:26.10 | async-http-client | no fix listed | UBUNTU-CVE-2026-102740 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| AsyncHttpClient | async-http-client | >= 2.0.0, < 2.16.1>= 3.0.0, < 3.0.12 |
Weakness: CWE-61, CWE-379, CWE-732 · Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:H/A:L
References
- https://github.com/AsyncHttpClient/async-http-client/security/advisories/GHSA-cf59-3jcr-vfhw x_refsource_CONFIRM
- https://github.com/AsyncHttpClient/async-http-client/pull/2281 x_refsource_MISC
- https://github.com/AsyncHttpClient/async-http-client/commit/0422e11c954c4b026e986d1458f7a7a2eab7e591 x_refsource_MISC
- https://github.com/AsyncHttpClient/async-http-client/commit/d945ce3357b093e74526871cd309832a717ecfda x_refsource_MISC
- https://github.com/AsyncHttpClient/async-http-client/releases/tag/async-http-client-project-2.16.1 x_refsource_MISC
- https://github.com/AsyncHttpClient/async-http-client/releases/tag/async-http-client-project-3.0.12 x_refsource_MISC