5.9

CVE-2026-85720: asynchttpclient async-http-client

CVSS: 5.9v3.1MediumAwaiting analysis
AliasesUBUNTU-CVE-2026-85720DEBIAN-CVE-2026-85720CGA-5mv7-75g7-4mm3
Published 17-09-2026Last modified 21-09-2026
Open JSON

Vulnerability summary

CVE-2026-85720 is a medium (CVSS 5.9) vulnerability in asynchttpclient async-http-client. EPSS estimates a 0.27% chance of exploitation in the next 30 days, higher than 17.2% of scored vulnerabilities.

Overall risk
24/100
0100
Low · default modelHow is this calculated?
CVSS score
5.9/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.27%
0%100%
Low · +0.01 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 17-09-2026
    PublishedVulnerability first disclosed.
  2. 21-09-2026
    Last modifiedVulnerability information updated.

Description

The AsyncHttpClient (AHC) library allows Java applications to easily execute HTTP requests and asynchronously process HTTP responses. From 2.0.0 until 2.16.1 and 3.0.12, a request using an HTTP proxy to reach an HTTPS origin can expose preemptive origin credentials because NettyRequestFactory and NettyRequestSender.sendRequestWithNewChannel attach Authorization to the plaintext CONNECT request before the TLS tunnel exists. Basic or Digest credentials and per-connection NTLM, Kerberos, or SPNEGO tokens intended for the origin are therefore visible to the proxy and to observers on the client-to-proxy hop. The tunneled request still receives origin Authorization after the tunnel is established, while Proxy-Authorization remains on CONNECT for its intended proxy recipient. This issue is fixed in versions 2.16.1 and 3.0.12.

CVSS metrics

7 scores · 7 sources · 1 version

EPSS trend

Probability

0.27%

Chance of exploitation in the next 30 days

Percentile

17%

Versus all other CVEs

30-day change

+0.01 pp

From 0.25% on 20-09-2026

20-09-202620-10-2026
EPSS score
0.27%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Chainguard8 products
  • apache-pulsar-4.0< 4.0.13-r5
  • apache-pulsar-4.2< 4.2.4-r4
  • apache-pulsar-fips-4.0< 4.0.13-r3
  • apache-pulsar-fips-4.2< 4.2.4-r4
  • druid< 37.0.0-r58
Wolfi3 products
  • apache-pulsar-4.2< 4.2.4-r4
  • druid< 37.0.0-r58
  • tez< 0.10.5-r31
Asynchttpclient1 product
Debian1 product
  • async-http-clientAll versions (No fix recorded)
Org.asynchttpclient1 product
  • async-http-client≥ 3.0.0, < 3.0.12 | ≥ 2.0.0, < 2.16.1
Ubuntu1 product
  • async-http-clientAll versions (No fix recorded)

6 vendors · 15 products

References

10 links