7.8

CVE-2024-49940: linux

CVSS: 7.8v3.1HighModified
AliasesUBUNTU-CVE-2024-49940DEBIAN-CVE-2024-49940
Published 21-10-2024Last modified 21-10-2026
Open JSON

Vulnerability summary

CVE-2024-49940 is a high (CVSS 7.8) vulnerability in linux. EPSS estimates a 0.24% chance of exploitation in the next 30 days, higher than 14.2% of scored vulnerabilities.

Overall risk
31/100
0100
Medium · default modelHow is this calculated?
CVSS score
7.8/10
010
High · v3.1 (CVE.org)
EPSS score
0.24%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 13 · Related 15
OPENSUSE-SU-2024:14500-1OPENSUSE-SU-2025:14705-1SUSE-SU-2025:01919-1SUSE-SU-2025:1177-1SUSE-SU-2025:1178-1SUSE-SU-2025:1180-1

Timeline

  1. 21-10-2024
    PublishedVulnerability first disclosed.
  2. 21-10-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

5 scores · 4 sources · 2 versions

EPSS trend

Probability

0.24%

Chance of exploitation in the next 30 days

Percentile

14%

Versus all other CVEs

30-day change

0.00 pp

From 0.24% on 21-09-2026

21-09-202621-10-2026
EPSS score
0.24%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

No weakness data has been published for this record.

Affected systems

Ubuntu138 products
  • linuxAll versions (No fix recorded)
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-awsAll versions (No fix recorded)
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Linux2 products
  • linux≥ 3953ae7b218df4d1e544b98a393666f9ae58a78c, < 98691b2e28a6c3dac0680914493d54c77f215755 | ≥ 3953ae7b218df4d1e544b98a393666f9ae58a78c, < f7415e60c25a6108cd7955a20b2e66b6251ffe02 | ≥ 3953ae7b218df4d1e544b98a393666f9ae58a78c, < 24256415d18695b46da06c93135f5b51c548b950 | b102bfc2a90d14f342580285782a9a51c74f7369 | 10c15ddabbcf888922adbdd44ca3fecf6eab19d9 | 8d1c650d452c53fcb3f02a7b1d772741639f89a4 | 12b5fb58ac993c24210cf8cbc72d407d3a4e6490 | aef37401b467a0b1a9517c69924a1d66937e0789 | ≥ 3.2.99, < 3.3 | ≥ 3.16.54, < 3.17 | ≥ 4.4.225, < 4.5 | ≥ 4.9.225, < 4.10 | ≥ 4.14.182, < 4.15 | 4.15
  • linux_kernel< 6.11.3
Debian1 product
  • linuxAll versions (No fix recorded) | < 6.11.4-1

3 vendors · 141 products

References

11 links
Show all 11 references