CVE-2026-31940 [High] | Security Vulnerability in Chamilo Lms

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 1.11.38 and 2.0.0-RC.3.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-04-11	—	0.04%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-04-11

—

0.04%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
7.5	3.1	HIGH	`CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:H) Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:R) A real person has to do something—click, install, enable—otherwise it doesn’t land. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:H) Serious risk that confidential data gets exposed in a big way. Integrity (I:H) They could widely tamper with or forge data—trust in the data is badly hurt. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	1.6	5.9	[email protected]
8.8	3.1	HIGH	`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:R) A real person has to do something—click, install, enable—otherwise it doesn’t land. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:H) Serious risk that confidential data gets exposed in a big way. Integrity (I:H) They could widely tamper with or forge data—trust in the data is badly hurt. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	2.8	5.9	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

7.5

3.1

HIGH

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H Click to expand

Attack vector (AV:N): Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H): Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N): No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R): A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H): Serious risk that confidential data gets exposed in a big way.
Integrity (I:H): They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

1.6

5.9

[email protected]

8.8

3.1

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H Click to expand

Attack vector (AV:N): Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N): No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R): A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H): Serious risk that confidential data gets exposed in a big way.
Integrity (I:H): They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

2.8

5.9

[email protected]

Affected software / configurations for CVE-2026-31940

Vendor	Product	Version	Raw CPE
chamilo	chamilo_lms	< 1.11.38	cpe:2.3:a:chamilo:chamilo_lms::::::::
chamilo	chamilo_lms	2.0.0	cpe:2.3:a:chamilo:chamilo_lms:2.0.0:alpha1::::::
chamilo	chamilo_lms	2.0.0	cpe:2.3:a:chamilo:chamilo_lms:2.0.0:alpha2::::::
chamilo	chamilo_lms	2.0.0	cpe:2.3:a:chamilo:chamilo_lms:2.0.0:alpha3::::::
chamilo	chamilo_lms	2.0.0	cpe:2.3:a:chamilo:chamilo_lms:2.0.0:alpha4::::::
chamilo	chamilo_lms	2.0.0	cpe:2.3:a:chamilo:chamilo_lms:2.0.0:alpha5::::::
chamilo	chamilo_lms	2.0.0	cpe:2.3:a:chamilo:chamilo_lms:2.0.0:beta1::::::
chamilo	chamilo_lms	2.0.0	cpe:2.3:a:chamilo:chamilo_lms:2.0.0:beta2::::::
chamilo	chamilo_lms	2.0.0	cpe:2.3:a:chamilo:chamilo_lms:2.0.0:beta3::::::
chamilo	chamilo_lms	2.0.0	cpe:2.3:a:chamilo:chamilo_lms:2.0.0:rc1::::::
chamilo	chamilo_lms	2.0.0	cpe:2.3:a:chamilo:chamilo_lms:2.0.0:rc2::::::

References for CVE-2026-31940

URL	Tags
https://github.com/chamilo/chamilo-lms/commit/ce0192c62e48c9d9474d915c541b3274844afbf9	Patch
https://github.com/chamilo/chamilo-lms/commit/e337b7cc74a0276a0b4f91f9282204d20cac1869	Patch
https://github.com/chamilo/chamilo-lms/security/advisories/GHSA-4gp7-cfjh-77gv	Vendor Advisory

URL

CVE-2026-31940 | Session Fixation in Chamilo LMS

Exploit prediction scoring system (EPSS) score for CVE-2026-31940

Common vulnerability scoring system (CVSS) metrics for CVE-2026-31940

Weakness enumeration for CVE-2026-31940

Affected software / configurations for CVE-2026-31940

References for CVE-2026-31940