CVE-2026-45300

HIGH
Published Jun 5, 2026 Modified Jun 8, 2026 CWE-200

Description

The AsyncHttpClient (AHC) library allows Java applications to easily execute HTTP requests and asynchronously process HTTP responses. Versions on the 2.x branch prior to 2.15.0 and the 3.x branch prior to 3.0.10 leak `Cookie` headers to cross-origin redirect targets. When following a redirect to a different origin, the `propagatedHeaders()` method in `Redirect30xInterceptor.java` strips `Authorization` and `Proxy-Authorization` headers but does not strip the `Cookie` header, causing session cookies and other sensitive cookie values to be sent to attacker-controlled servers. Versions 2.15.0 and 3.0.10 patch the issue.

CVSS v3.1 Score

7.4
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N

EPSS — Exploit Prediction

0.0032
Probability of exploitation
0.24%
Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-200 CWE-200

Affected Products

Vendor Product
asynchttpclient_project async-http-client
asynchttpclient_project async-http-client

References

Frequently Asked Questions

What is CVE-2026-45300? +
The AsyncHttpClient (AHC) library allows Java applications to easily execute HTTP requests and asynchronously process HTTP responses. Versions on the 2.x branch prior to 2.15.0 and the 3.x branch prior to 3.0.10 leak `Cookie` headers to cross-origin redirect targets. When following a redirect to a different origin, the `propagatedHeaders()` method in `Redirect30xInterceptor.java` strips `Authorization` and `Proxy-Authorization` headers but does not strip the `Cookie` header, causing session cookies and other sensitive cookie values to be sent to attacker-controlled servers. Versions 2.15.0 and 3.0.10 patch the issue. It has a CVSS v3.1 base score of 7.4 (HIGH).
How severe is CVE-2026-45300? +
CVE-2026-45300 has a CVSS v3.1 score of 7.4 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0032, placing it in the 0th percentile for exploitation probability.
What products are affected by CVE-2026-45300? +
CVE-2026-45300 affects products from asynchttpclient_project, specifically: async-http-client. Check the affected products table above for specific version ranges.
How do I check if I'm vulnerable to CVE-2026-45300? +
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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