Security readout for executives and security teams
Plain-English summary
CVE-2024-46763 is a Linux kernel networking flaw that can crash a system when FOU tunnel traffic is processed during tunnel, network-namespace, or host teardown. Its documented impact is loss of availability, not data theft or modification. The supplied CVSS score is 7.5.
Executive priority
Treat as high priority for exposed infrastructure using FOU tunnels or dynamic network namespaces because successful triggering can crash the host. For systems without FOU use, validate exposure before emergency action. Patch through normal vendor-supported kernel channels and track reboot completion.
Technical view
A teardown race can clear a tunnel socket’s sk_user_data while an in-flight UDP GRO receive path still calls fou_gro_receive(). Dereferencing the cleared pointer causes a kernel NULL-pointer fault. The stable fix uses RCU-safe access and adds NULL checks to the FOU GRO handlers.
Likely exposure
Exposure is most relevant to Linux systems using FOU tunnelling and GRO where traffic can overlap tunnel or network-namespace teardown. The bundle identifies multiple affected kernel lines, but distribution backports may change status. Confirm the running kernel against vendor advisories and the referenced stable fixes.
Exploitation context
The CVSS vector describes unauthenticated network reachability and high availability impact. However, the supplied record is not in KEV and provides no evidence of active exploitation or a public exploit. The documented failure was observed during host shutdown, so practical exploitability remains incompletely established.
Researcher notes
The fault is a lifetime synchronization issue between udp_tunnel_sock_release() and an in-flight UDP GRO path. sk_user_data becomes NULL before socket destruction, but fou_gro_receive() may still execute. The fix combines rcu_dereference_sk_user_data() with NULL handling. The supplied sources establish denial of service, not code execution.
Mitigation direction
- Upgrade to a vendor-supported kernel containing the applicable referenced stable fix or distribution backport.
- Prioritize systems actively using FOU tunnels, network namespaces, or frequent tunnel teardown.
- If immediate upgrading is impossible, check vendor guidance for supported temporary mitigations.
- Schedule controlled reboots where required to activate the updated kernel.
Validation and detection
- Inventory running kernel versions and identify hosts using FOU tunnelling.
- Compare vendor package status with the referenced Linux stable fixes and Debian advisories.
- Confirm each updated host booted into the remediated kernel.
- Review kernel logs for FOU GRO NULL-pointer faults or unexplained networking-related crashes.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
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CVE-2024-46763 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 7.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6LinuxVulnerability scoring details
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://git.kernel.org/stable/c/231c235d2f7a66f018f172e26ffd47c363f244efCVE reference, Linux
- https://git.kernel.org/stable/c/4494bccb52ffda22ce5a1163a776d970e6229e08CVE reference, Linux
- https://git.kernel.org/stable/c/d7567f098f54cb53ee3cee1c82e3d0ed9698b6b3CVE reference, Linux
- https://git.kernel.org/stable/c/1df42be305fe478ded1ee0c1d775f4ece713483bCVE reference, Linux
- https://git.kernel.org/stable/c/c46cd6aaca81040deaea3500ba75126963294bd9CVE reference, Linux
- https://git.kernel.org/stable/c/7e4196935069947d8b70b09c1660b67b067e75cbCVE reference, Linux
- https://lists.debian.org/debian-lts-announce/2025/01/msg00001.htmlCVE reference, CVE
- https://lists.debian.org/debian-lts-announce/2024/10/msg00003.htmlCVE reference, CVE
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.