DEBIAN-CVE-2024-49940

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Source
https://security-tracker.debian.org/tracker/DEBIAN-CVE-2024-49940
Import Source
https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2024-49940.json
JSON Data
https://api.test.osv.dev/v1/vulns/DEBIAN-CVE-2024-49940
Upstream
Published
2024-10-21T18:15:15Z
Modified
2025-09-19T06:05:10Z
Summary
[none]
Details

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, l2tpsessionfree drops the tunnel refcount if session->tunnel is non-NULL. However, session->tunnel is set in l2tpsessioncreate, before the tunnel refcount is incremented by l2tpsessionregister, which leaves a small window where session->tunnel is non-NULL when the tunnel refcount hasn't been bumped. Moving the assignment to l2tpsessionregister is trivial but l2tpsessioncreate calls l2tpsessionsetheaderlen which uses session->tunnel to get the tunnel's encap. Add an encap arg to l2tpsessionsetheaderlen to avoid using session->tunnel. If l2tpv3 sessions have colliding IDs, it is possible for l2tpv3sessionget to race with l2tpsession_register and fetch a session which doesn't yet have session->tunnel set. Add a check for this case.

References

Affected packages

Debian:13 / linux

Package

Name
linux
Purl
pkg:deb/debian/linux?arch=source

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
6.11.4-1

Ecosystem specific 

{
    "urgency": "not yet assigned"
}

Debian:14 / linux

Package

Name
linux
Purl
pkg:deb/debian/linux?arch=source

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
6.11.4-1

Ecosystem specific 

{
    "urgency": "not yet assigned"
}