Cyber Resilience

CVE-2026-15571

Published
18 August 2026
Modified
19 August 2026
CVSS Score v3.1 7.3
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N
EPSS Score 0.0031 24th percentile
Risk Priority 53 floored blend · peak EPSS

Summary

CVE-2026-15571 is a high-severity Predictable from Observable State (CWE-341) vulnerability. Its CVSS base score is 7.3 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Browser Session Hijacking (T1185); ranked at the 24th 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 IA-5 (Authenticator Management) and SC-12 (Cryptographic Key Establishment and Management) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

A flaw was found in the legacy client-initiated account-linking endpoint of Keycloak, a widely used open-source identity and access management solution. The mechanism used to protect the account-linking process from unauthorized requests relies on a hash that can be predicted…

more

by a malicious OIDC client. By tricking a user into authenticating, an attacker-controlled client can forge a valid linking URL to connect the victim's account to an attacker's external identity. This results in a full account takeover, allowing the attacker to log in as the victim.

CWE(s)
CWE-341

Related Threats

MITRE ATT&CK Enterprise Techniques

T1185 Browser Session Hijacking Collection
Adversaries may take advantage of security vulnerabilities and inherent functionality in browser software to change content, modify user-behaviors, and intercept information as part of various browser session hijacking techniques.
attack.mitre.org →
T1563 Remote Service Session Hijacking Lateral Movement
Adversaries may take control of preexisting sessions with remote services to move laterally in an environment.
attack.mitre.org →
T1606 Forge Web Credentials Credential Access
Adversaries may forge credential materials that can be used to gain access to web applications or Internet services.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-40780Shared CWE-341
CVE-2026-38968Shared CWE-341
CVE-2025-42925Shared CWE-341
CVE-2025-48461Shared CWE-341
CVE-2026-42365Shared CWE-341
CVE-2024-10141Shared CWE-341
CVE-2023-49259Shared CWE-341
CVE-2026-36609Shared CWE-341
CVE-2026-5081Shared CWE-341
CVE-2026-40164Shared CWE-341

Affected Assets

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)
  • V6.6.1
  • V6.5.1
  • V6.5.3
  • V6.5.5

Mitigating Controls (NIST 800-53 r5) AI

IA-5 Authenticator Management good match

Authenticator management requires generation and distribution of values that cannot be derived from observable state.

SC-12 Cryptographic Key Establishment and Management good match

Cryptographic key establishment mandates use of unpredictable, non-observable values for keys and nonces.

SC-23 Session Authenticity good match

Session authenticity protection requires session identifiers or tokens that resist prediction from network or timing observations.

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-06 mostly match
prevents

Secure SDLC practices directly require cryptographically secure random values instead of observable state such as time or PID.

PR.PS-01 partial match
prevents

Hardened configuration baselines can enforce use of cryptographically secure RNG sources and disable predictable state-based mechanisms.

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.8.24 Use of cryptography mostly match
prevents

Cryptographic controls replace predictable values with high-entropy, non-guessable material.

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

Security testing can detect predictability issues but does not prevent them by itself.

A.8.25 Secure development life cycle partial match
prevents

SDLC requirements encourage secure design but do not directly mandate removal of predictable state.

A.8.28 Secure coding partial match
prevents

Secure coding practices explicitly forbid use of predictable state (time, PID, counters) for secrets or tokens.

A.8.5 Secure authentication partial match
prevents

Strong authentication mechanisms reduce reliance on predictable state-derived tokens or identifiers.

A.8.17 Clock synchronization none match
none

Accurate time sources limit one observable state vector but do not address broader predictability.

References