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NVD / CVE Program· CNA GitHub_M

CVE-2026-55688: AsyncHttpClient: Cookie stored for an unrelated domain (cookie tossing) via ThreadSafeCookieStore

Noroxi assessment

Priority: Monitor (action score 16/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.33% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. Special conditions such as timing or configuration are required.
  • Fixed version: async-http-client (Debian:12) 2.12.3-1+deb12u1; org.asynchttpclient:async-http-client (Maven) 2.16.0, 3.0.11.

Low priority for now. Upgrade to async-http-client (Debian:12) 2.12.3-1+deb12u1; org.asynchttpclient:async-http-client (Maven) 2.16.0, 3.0.11 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

MediumCVSS 4.0 · v3.1—No exploit Fix available
Published
Jul 1, 2026
Updated
Oct 25, 2026
EPSS
0.3% · 26th percentile

Report tools

JSON

Action score

16

Monitor

Low priority for now.

CVSS
16 / 40 · 4.0 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.3%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · GitHub_M
4.0
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • AsyncHttpClient async-http-client

    • >= 2.0.0, < 2.16.0, >= 3.0.0.Beta1, < 3.0.11affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12async-http-clientbefore 2.12.3-1+deb12u12.12.3-1+deb12u1
Mavenorg.asynchttpclient:async-http-clientfrom 2.0.0 · before 2.16.02.16.0
Mavenorg.asynchttpclient:async-http-clientfrom 3.0.0.Beta1 · before 3.0.113.0.11

Same product

asynchttpclient: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-107282AsyncHttpClient: Replay to a different host sends the original host request and credentials to the new host
    37Monitor
  • CVE-2024-53990AsyncHttpClient (AHC) library's `CookieStore` replaces explicitly defined `Cookie`s
    36Monitor
  • CVE-2026-107279AsyncHttpClient: Digest mutual authentication is switched off by a peer offering qop=auth-int
    35Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-40490Apr 17, 2026 · AsyncHttpClient leaks authorization credentials to untrusted domains on cross-origin redirects
    27Monitor
  • Later →CVE-2026-85719Sep 17, 2026 · AsyncHttpClient: SOCKS proxy credentials sent to the origin server over plaintext HTTP
    30Monitor
  • Later →CVE-2026-85716Sep 17, 2026 · AsyncHttpClient: SCRAM and Digest mutual-authentication responses are not verified
    14Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
debian:async-http-client2.12.3-1+deb12u1 · Debian:12Package registry (OSV)
Maven:org.asynchttpclient:async-http-client2.16.0Package registry (OSV)
Maven:org.asynchttpclient:async-http-client3.0.11Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-10728098 days apartAsyncHttpClient: Cookie Domain attribute is not checked against the public suffix list, so a cookie can be set for co.uk
    27Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
none
Integrity
low · data or configuration can be modified
Availability
none

Impact can extend beyond the vulnerable component (scope changes).

Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Changed
Confidentiality impact
None
Integrity impact
Low
Availability impact
None

Weakness class (CWE)

CWE-1275 · Sensitive Cookie with Improper SameSite Attribute

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

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References

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records