CVE-2026-102740: Permission Flaw (CVSS 5.8)

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.

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CVSS v3.1 Score

5.8

MEDIUM

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:H/A:L

Weakness Type (CWE)

CWE-61 CWE-61

CWE-379 CWE-379

CWE-732 CWE-732

References

Other References

https://github.com/AsyncHttpClient/async-http-client/commit/0422e11c954c4b026e986d1458f7a7a2eab7e591 https://github.com/AsyncHttpClient/async-http-client/commit/d945ce3357b093e74526871cd309832a717ecfda https://github.com/AsyncHttpClient/async-http-client/pull/2281 https://github.com/AsyncHttpClient/async-http-client/releases/tag/async-http-client-project-2.16.1 https://github.com/AsyncHttpClient/async-http-client/releases/tag/async-http-client-project-3.0.12 https://github.com/AsyncHttpClient/async-http-client/security/advisories/GHSA-cf59-3jcr-vfhw

Frequently Asked Questions

What is CVE-2026-102740? +

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. It has a CVSS v3.1 base score of 5.8 (MEDIUM).

How severe is CVE-2026-102740? +

CVE-2026-102740 has a CVSS v3.1 score of 5.8 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

How do I check if I'm vulnerable to CVE-2026-102740? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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