Answer in brief
CVE-2024-49940 records a Unknown severity vulnerability in l2tp: prevent possible tunnel refcount underflow. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=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 | f7415e60c25a6108cd7955a20b2e66b6251ffe02, 24256415d18695b46da06c93135f5b51c548b950, 3.3, 3.17, 4.5, 4.10, 4.15 |
| Linux/Linuxgeneric | 4.15 | Not reported |
Published upstream
Oct 21, 2024
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 5, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 5, 2026
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.
Quoted source text, attributed separately from HOL analysis.
Answer in brief
CVE-2024-49940 records a Unknown severity vulnerability in l2tp: prevent possible tunnel refcount underflow. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=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 | f7415e60c25a6108cd7955a20b2e66b6251ffe02, 24256415d18695b46da06c93135f5b51c548b950, 3.3, 3.17, 4.5, 4.10, 4.15 |
| Linux/Linuxgeneric | 4.15 | Not reported |
Published upstream
Oct 21, 2024
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 5, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 5, 2026
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.
Quoted source text, attributed separately from HOL analysis.