CVE-2024-49940

Nov. 13, 2024, 1:26 p.m.

5.5
Medium

Description

In the Linux kernel, the following vulnerability has been resolved: l2tp: prevent possible tunnel refcount underflow When a session is created, it sets a backpointer to its tunnel. When the session refcount drops to 0, l2tp_session_free drops the tunnel refcount if session->tunnel is non-NULL. However, session->tunnel is set in l2tp_session_create, before the tunnel refcount is incremented by l2tp_session_register, which leaves a small window where session->tunnel is non-NULL when the tunnel refcount hasn't been bumped. Moving the assignment to l2tp_session_register is trivial but l2tp_session_create calls l2tp_session_set_header_len which uses session->tunnel to get the tunnel's encap. Add an encap arg to l2tp_session_set_header_len to avoid using session->tunnel. If l2tpv3 sessions have colliding IDs, it is possible for l2tp_v3_session_get to race with l2tp_session_register and fetch a session which doesn't yet have session->tunnel set. Add a check for this case.

Product(s) Impacted

Vendor Product Versions
Linux
  • Linux Kernel
  • *

Weaknesses

Common security weaknesses mapped to this vulnerability.

*CPE(s)

Affected systems and software identified for this CVE.

Type Vendor Product Version Update Edition Language Software Edition Target Software Target Hardware Other Information
o linux linux_kernel / / / / / / / /

References

https://git.kernel.org/stable/c/24256415d18695b46da06c93135f5b51c548b950
https://git.kernel.org/stable/c/f7415e60c25a6108cd7955a20b2e66b6251ffe02

Tags

416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD-CWE-noinfo
2024-10-21
CVE-2024-49940

CVSS Score

5.5 / 10

CVSS Data - 3.1

  • Attack Vector: LOCAL
  • Attack Complexity: LOW
  • Privileges Required: LOW
  • Scope: UNCHANGED
  • Confidentiality Impact: NONE
  • Integrity Impact: NONE
  • Availability Impact: HIGH

    • CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

    View Vector String

Timeline

Published: Oct. 21, 2024, 6:15 p.m.
Last Modified: Nov. 13, 2024, 1:26 p.m.

Status : Analyzed

CVE has been recently published to the CVE List and has been received by the NVD.

More info

Source

416baaa9-dc9f-4396-8d5f-8c081fb06d67

*Disclaimer: Some vulnerabilities do not have an associated CPE. To enhance the data, we use AI to infer CPEs based on CVE details. This is an automated process and might not always be accurate.