Cyber Resilience

CVE-2026-55688

Published
01 July 2026
Modified
06 August 2026
CVSS Score v3.1 4.0
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N
EPSS Score 0.0022 13th percentile
Risk Priority 33 floored blend · peak EPSS

Summary

CVE-2026-55688 is a medium-severity Sensitive Cookie with Improper SameSite Attribute (CWE-1275) vulnerability. Its CVSS base score is 4.0 (Medium).

Operationally, ranked at the 13th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to CM-6 (Configuration Settings) and SC-23 (Session Authenticity) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A01:2025 Broken Access Control

EU & UK References

Vulnerability Data

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…

more

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.

CWE(s)
CWE-1275

Related Threats

CVEs Like This One

CVE-2024-43173Shared CWE-1275
CVE-2024-30155Shared CWE-1275
CVE-2025-36134Shared CWE-1275
CVE-2025-52628Shared CWE-1275
CVE-2024-6611Shared CWE-1275
CVE-2024-42212Shared CWE-1275
CVE-2023-53957Shared CWE-1275
CVE-2026-8433Shared CWE-1275
CVE-2026-8410Shared CWE-1275
CVE-2026-8434Shared CWE-1275

Affected Assets

—
In
inferred from references and description; NVD did not file a CPE for this CVE

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V3.3.2

Mitigating Controls (NIST 800-53 r5) AI

CM-6 Configuration Settings good match

Establishing secure configuration settings for web components includes requiring appropriate SameSite attributes on sensitive cookies.

SC-23 Session Authenticity good match

Proper SameSite settings on session cookies directly help protect the authenticity of communications sessions against cross-site misuse.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-01 mostly match
prevents

Secure configuration baselines and enforcement directly require proper SameSite settings on sensitive cookies.

PR.PS-06 mostly match
prevents

Secure SDLC practices include coding standards and reviews that mandate correct SameSite attributes.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing can detect missing SameSite attributes but does not prevent the weakness.

A.8.26 Application security requirements partial match
prevents

Application security requirements can mandate SameSite attributes on sensitive cookies.

A.8.28 Secure coding partial match
prevents

Secure coding standards directly require proper SameSite settings to prevent CSRF.

References