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CVE-2026-55688: asynchttpclient async-http-client

CVSS: 4.0v3.1MediumAwaiting analysis
AliasesUBUNTU-CVE-2026-55688USN-8655-1DEBIAN-CVE-2026-55688
Published 01-07-2026Last modified 06-08-2026
Open JSON

Vulnerability summary

CVE-2026-55688 is a medium (CVSS 4.0) vulnerability in asynchttpclient async-http-client. EPSS estimates a 0.33% chance of exploitation in the next 30 days, higher than 24.7% of scored vulnerabilities.

Overall risk
16/100
0100
Low · default modelHow is this calculated?
CVSS score
4.0/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.33%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 0 · Related 1
CGA-V485-2JRM-HRH2

Timeline

  1. 01-07-2026
    PublishedVulnerability first disclosed.
  2. 06-08-2026
    Last modifiedVulnerability information updated.

Description

The AsyncHttpClient (AHC) library allows Java applications to easily execute HTTP requests and asynchronously process HTTP responses. In versions from 2.0.0 prior to 2.16.0 and from 3.0.0.Beta1 prior to 3.0.11, ThreadSafeCookieStore stored a cookie under the value of its Domain attribute without verifying that the responding host is allowed to set a cookie for that domain, leading to a cookie tossing / cookie injection issue. A host the client connects to can therefore plant a cookie scoped to an unrelated domain, and the client will then send that cookie on later requests to that domain. Applications that use a single AsyncHttpClient instance - and thus the default, shared CookieStore - to reach both an attacker-influenced host and a trusted host are impacted. This issue has been fixed in versions 2.16.0 and 3.0.11.

CVSS metrics

7 scores · 7 sources · 1 version

EPSS trend

Probability

0.33%

Chance of exploitation in the next 30 days

Percentile

25%

Versus all other CVEs

30-day change

0.00 pp

From 0.33% on 20-09-2026

20-09-202620-10-2026
EPSS score
0.33%

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

Chainguard10 products
  • apache-pulsar-4.0< 4.0.13-r3
  • apache-pulsar-4.1< 4.1.3-r16
  • apache-pulsar-4.2< 4.2.4-r3
  • apache-pulsar-fips-4.0< 4.0.13-r1
  • apache-pulsar-fips-4.1< 4.1.3-r13
Wolfi4 products
  • apache-pulsar-4.1< 4.1.3-r16
  • apache-pulsar-4.2< 4.2.4-r3
  • druid< 37.0.0-r56 | < 37.0.0-r55
  • tez< 0.10.5-r29
Asynchttpclient1 product
Debian1 product
  • async-http-client< 2.12.3-1+deb12u1
Org.asynchttpclient1 product
  • async-http-client≥ 3.0.0.Beta1, < 3.0.11 | ≥ 2.0.0, < 2.16.0
Ubuntu1 product
  • async-http-clientAll versions (No fix recorded) | < 2.6.0-1ubuntu0.1~esm1 | < 2.12.3-1ubuntu0.22.04.1 | < 2.12.3-1ubuntu0.24.04.1 | < 2.12.3-1ubuntu1.1

6 vendors · 18 products

References

15 links
Show all 15 references