Cyber Resilience

CVE-2026-40082

Auth Bypass in Cacti ≤ 1.2.31

Public PoCAuth Bypass
Published
25 June 2026
Modified
29 June 2026
Patch / advisory
View advisory
CVSS Score v3.1 5.4
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
EPSS Score 0.0023 14th percentile
Risk Priority 42 floored blend · peak EPSS

Summary

CVE-2026-40082 is a medium-severity Session Fixation (CWE-384) vulnerability in Cacti Cacti. Its CVSS base score is 5.4 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Steal Web Session Cookie (T1539); ranked at the 14th 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 SC-23 (Session Authenticity) and AC-12 (Session Termination) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A07:2025 Authentication Failures

EU & UK References

Vulnerability Data

Cacti is an open source performance and fault management framework. Versions 1.2.30 and prior have missing session_regenerate_id() after login, leading to Session Fixation. session_regenerate_id() is NOT called after successful login. The login flow at auth_login.php:203-207 directly sets $_SESSION[SESS_USER_ID] without rotating…

more

the session ID. The session cookie configuration is otherwise good (httponly=true, samesite=Strict, secure=true for HTTPS at include/global.php:513-537), but these do not prevent session fixation via same-site vectors. This issue has been fixed in version 1.2.31.

CWE(s)
CWE-384

Related Threats

MITRE ATT&CK Enterprise Techniques

T1539 Steal Web Session Cookie Credential Access
An adversary may steal web application or service session cookies and use them to gain access to web applications or Internet services as an authenticated user without needing credentials.
attack.mitre.org →
T1550.004 Web Session Cookie Lateral Movement
Adversaries can use stolen session cookies to authenticate to web applications and services.
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-2024-43364Same product: Cacti Cacti
CVE-2023-49088Same product: Cacti Cacti
CVE-2023-50250Same product: Cacti Cacti
CVE-2024-43365Same product: Cacti Cacti
CVE-2026-39900Same product: Cacti Cacti
CVE-2023-49086Same product: Cacti Cacti
CVE-2026-39897Same product: Cacti Cacti
CVE-2024-27082Same product: Cacti Cacti
CVE-2024-43362Same product: Cacti Cacti
CVE-2023-49085Same product: Cacti Cacti

Affected Assets

cacti
cacti
≤ 1.2.31

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)
  • V4.4.4
  • V7.6.2

Mitigating Controls (NIST 800-53 r5) AI

SC-23 Session Authenticity good match

Requires protection of session authenticity, which directly stops an attacker from using a stolen or fixed session identifier after authentication.

AC-12 Session Termination partial match

Limits the lifetime of any session (fixed or not), thereby reducing the window during which a stolen identifier remains usable.

AC-3 Access Enforcement partial match

Enforces that only properly authorized (i.e., freshly authenticated) sessions can access resources, making a pre-existing fixed session ID unusable.

IA-11 Re-authentication partial match

Forces re-authentication under defined conditions, which should result in issuance of a fresh session identifier and invalidation of any prior one.

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 mostly match
prevents

Proper authentication processes must invalidate prior session identifiers to prevent fixation attacks.

PR.AA-01 partial match
prevents

Managing identities and credentials includes handling session identifiers as temporary credentials that must be invalidated on re-authentication.

PR.AA-04 partial match
prevents

Protecting and verifying identity assertions encompasses secure handling and regeneration of session tokens.

PR.PS-01 partial match
prevents

Configuration baselines can enforce session regeneration and timeout settings that block fixation.

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 session-fixation issues, yet the weakness absence does not replace comprehensive testing.

A.5.15 Access control partial match
degrades

Access-control policy can mandate session invalidation on re-authentication, but does not prescribe the technical mechanism.

A.5.16 Identity management partial match
degrades

Identity-management procedures can require new session tokens after login, yet the control is broader than session handling.

A.5.17 Authentication information partial match
degrades

Authentication-information rules can include session-token lifecycle requirements, but the control focuses on credential management.

A.8.25 Secure development life cycle partial match
prevents

Secure-SDLC requirement can embed session-fixation checks, but eliminating the weakness does not satisfy the full SDLC control.

A.8.26 Application security requirements partial match
prevents

Application-security requirements can specify session handling, yet the weakness fix alone does not meet the broader requirement.

References