Raw vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:HSummary
CVE-2026-31940 is a high-severity Session Fixation (CWE-384) vulnerability in Chamilo Chamilo Lms. Its CVSS base score is 7.5 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Steal Web Session Cookie (T1539); ranked at the 15th 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 SC-23 (Session Authenticity) and AC-12 (Session Termination) — 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-2026-31940 is a session fixation vulnerability affecting Chamilo LMS, an open-source learning management system. In versions prior to 1.11.38 and 2.0.0-RC.3, the component main/lp/aicc_hacp.php directly uses user-controlled request parameters to set the PHP session ID before loading the global bootstrap file. This flaw, classified under CWE-384 (Session Fixation), carries a CVSS v3.1 base score of 7.5 (AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H) and was published on 2026-04-10.
The vulnerability can be exploited remotely by unauthenticated attackers (PR:N) over the network (AV:N), though it requires high attack complexity (AC:H) and user interaction (UI:R), with unchanged scope (S:U). By controlling the session ID via manipulated request parameters, an attacker can force a victim's browser to use a predetermined session identifier. If the victim subsequently authenticates, the attacker may hijack the session, achieving high impacts on confidentiality, integrity, and availability.
Mitigation is provided in Chamilo LMS versions 1.11.38 and 2.0.0-RC.3, which address the issue by preventing direct use of user-controlled parameters for session ID setting. Patch details are available in GitHub commits ce0192c62e48c9d9474d915c541b3274844afbf9 and e337b7cc74a0276a0b4f91f9282204d20cac1869, with additional guidance in the security advisory at GHSA-4gp7-cfjh-77gv.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-21522
Vulnerability Data
Chamilo LMS is a learning management system. Prior to 1.11.38 and 2.0.0-RC.3, in main/lp/aicc_hacp.php, user-controlled request parameters are directly used to set the PHP session ID before loading global bootstrap. This leads to session fixation. This vulnerability is fixed in…
more
1.11.38 and 2.0.0-RC.3.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V4.4.4V7.6.2
Mitigating Controls (NIST 800-53 r5) AI
Requires protection of session authenticity, which directly stops an attacker from using a stolen or fixed session identifier after authentication.
Limits the lifetime of any session (fixed or not), thereby reducing the window during which a stolen identifier remains usable.
Enforces that only properly authorized (i.e., freshly authenticated) sessions can access resources, making a pre-existing fixed session ID unusable.
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.
Proper authentication processes must invalidate prior session identifiers to prevent fixation attacks.
Managing identities and credentials includes handling session identifiers as temporary credentials that must be invalidated on re-authentication.
Protecting and verifying identity assertions encompasses secure handling and regeneration of session tokens.
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.
Security testing can detect session-fixation issues, yet the weakness absence does not replace comprehensive testing.
Access-control policy can mandate session invalidation on re-authentication, but does not prescribe the technical mechanism.
Identity-management procedures can require new session tokens after login, yet the control is broader than session handling.
Authentication-information rules can include session-token lifecycle requirements, but the control focuses on credential management.
Secure-SDLC requirement can embed session-fixation checks, but eliminating the weakness does not satisfy the full SDLC control.
Application-security requirements can specify session handling, yet the weakness fix alone does not meet the broader requirement.