Cyber Resilience

CVE-2026-27575

Vikunja ≤ 2.0.0

Public PoC
Published
25 February 2026
Modified
05 March 2026
Patch / advisory
View advisory
CVSS Score v3.1 9.1
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
EPSS Score 0.0043 35th percentile
Risk Priority 67 floored blend · peak EPSS

Summary

CVE-2026-27575 is a critical-severity Weak Password Requirements (CWE-521) vulnerability in Vikunja Vikunja. Its CVSS base score is 9.1 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Brute Force (T1110); ranked at the 35th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to AC-12 (Session Termination) and IA-5 (Authenticator Management) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2026-27575 affects Vikunja, an open-source self-hosted task management platform, in versions prior to 2.0.0. The vulnerability combines two issues: the lack of enforcement for minimum password strength requirements, allowing users to set weak passwords such as "1234" or "password," and the persistence of active sessions even after a user changes their password. Rated at CVSS 9.1 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N) and linked to CWE-521 (Weak Password Requirements) and CWE-613 (Insufficient Session Expiration), it enables unauthorized account access without requiring privileges or user interaction.

An unauthenticated attacker can exploit this over the network with low complexity by compromising an account through brute-force attacks or credential stuffing on weak passwords. Once access is gained, the attacker maintains persistent access via the unchanged session, even if the legitimate user resets their password, potentially leading to high confidentiality and integrity impacts such as data exfiltration, task manipulation, or further lateral movement within the self-hosted environment.

The GitHub security advisory (GHSA-3ccg-x393-96v8) and Vikunja changelog for version 2.0.0 detail the fix, which addresses both password strength enforcement and session invalidation on password changes. Security practitioners should upgrade to Vikunja 2.0.0 or later and audit existing user passwords for weakness, implementing additional controls like rate limiting and multi-factor authentication where possible.

OWASP Top 10 for Web (2025)

A07:2025 Authentication Failures

EU & UK References

Vulnerability Data

Vikunja is an open-source self-hosted task management platform. Prior to version 2.0.0, the application allows users to set weak passwords (e.g., 1234, password) without enforcing minimum strength requirements. Additionally, active sessions remain valid after a user changes their password. An…

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attacker who compromises an account (via brute-force or credential stuffing) can maintain persistent access even after the victim resets their password. Version 2.0.0 contains a fix.

CWE(s)
CWE-521CWE-613

Related Threats

MITRE ATT&CK Enterprise Techniques

T1110 Brute Force Credential Access
Adversaries may use brute force techniques to gain access to accounts when passwords are unknown or when password hashes are obtained.
attack.mitre.org →
T1110.001 Password Guessing Credential Access
Adversaries with no prior knowledge of legitimate credentials within the system or environment may guess passwords to attempt access to accounts.
attack.mitre.org →
T1110.002 Password Cracking Credential Access
Adversaries may use password cracking to attempt to recover usable credentials, such as plaintext passwords, when credential material such as password hashes are obtained.
attack.mitre.org →
T1110.003 Password Spraying Credential Access
Adversaries may use a single or small list of commonly used passwords against many different accounts to attempt to acquire valid account credentials.
attack.mitre.org →
T1133 External Remote Services Persistence
Adversaries may leverage external-facing remote services to initially access and/or persist within a network.
attack.mitre.org →
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 →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-35594Same product: Vikunja Vikunja
CVE-2026-35597Same product: Vikunja Vikunja
CVE-2026-28268Same product: Vikunja Vikunja
CVE-2026-35600Same product: Vikunja Vikunja
CVE-2026-27116Same product: Vikunja Vikunja
CVE-2026-27616Same product: Vikunja Vikunja
CVE-2026-25935Same product: Vikunja Vikunja
CVE-2026-33473Same product: Vikunja Vikunja
CVE-2026-34727Same product: Vikunja Vikunja
CVE-2026-33334Same product: Vikunja Vikunja

Affected Assets

vikunja
vikunja
≤ 2.0.0

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 2 hardening rules · 1 OS baseline
Validate
Prove the fix (OWASP ASVS)
  • V6.2.4
  • V6.2.9
  • V6.2.12
  • V6.4.1

Mitigating Controls (NIST 800-53 r5) AI

AC-12 Session Termination good match

AC-12 directly requires automatic session termination after a defined period, structurally preventing reuse of expired session identifiers.

IA-5 Authenticator Management good match

IA-5 directly requires organizations to enforce strength, complexity, and change rules for passwords and other authenticators at issuance and reset.

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.AA-03 full match
prevents

Explicitly requires enforcing minimum password strength as part of authentication.

PR.AA-01 mostly match
prevents

Credential lifecycle management directly includes enforcing session expiration to prevent reuse.

PR.AA-05 mostly match
prevents

Authorization policy enforcement and review covers terminating stale sessions to limit access scope.

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.5.17 Authentication information mostly match
prevents

Enforcing minimum length, complexity, non-dictionary, and non-reuse rules directly counters weak password policies that allow attackers to guess or brute-force credentials.

A.8.5 Secure authentication none match
none

Automatic termination of inactive sessions and limits on connection duration shrink the window during which a hijacked or unattended authenticated session can be exploited.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

RHEL 7 (2 rules)
  • V-204424 The Red Hat Enterprise Linux operating system must not allow accounts configured with blank or null passwords. prevents CWE-521
  • V-204425 The Red Hat Enterprise Linux operating system must be configured so that the SSH daemon does not allow authentication using an empty password. prevents CWE-521

References