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CVE Record

CVE-2022-49973: skmsg: Fix wrong last sg check in sk_msg_recvmsg()

In the Linux kernel, the following vulnerability has been resolved: skmsg: Fix wrong last sg check in sk_msg_recvmsg() Fix one kernel NULL pointer dereference as below: [ 224.462334] Call Trace: [ 224.462394] __tcp_bpf_recvmsg+0xd3/0x380 [ 224.462441] ? sock_has_perm+0x78/0xa0 [ 224.462463] tcp_bpf_recvmsg+0x12e/0x220 [ 224.462494] inet_recvmsg+0x5b/0xd0 [ 224.462534] __sys_recvfrom+0xc8/0x130 [ 224.462574] ? syscall_trace_enter+0x1df/0x2e0 [ 224.462606] ? __do_page_fault+0x2de/0x500 [ 224.462635] __x64_sys_recvfrom+0x24/0x30 [ 224.462660] do_syscall_64+0x5d/0x1d0 [ 224.462709] entry_SYSCALL_64_after_hwframe+0x65/0xca In commit 9974d37ea75f ("skmsg: Fix invalid last sg check in sk_msg_recvmsg()"), we change last sg check to sg_is_last(), but in sockmap redirection case (without stream_parser/stream_verdict/ skb_verdict), we did not mark the end of the scatterlist. Check the sk_msg_alloc, sk_msg_page_add, and bpf_msg_push_data functions, they all do not mark the end of sg. They are expected to use sg.end for end judgment. So the judgment of '(i != msg_rx->sg.end)' is added back here.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

This is a Linux kernel bug in a TCP/BPF message handling path. Under the affected code path, the kernel can hit a NULL pointer dereference. The public sources do not provide CVSS scoring, exploitation evidence, or proof of data compromise, so treat the primary known risk as availability until vendor guidance says otherwise.

Executive priority

Track this through routine Linux kernel patch management unless your environment heavily uses eBPF sockmap features or hosts untrusted workloads. The available evidence supports attention, not emergency response.

Technical view

The issue is in sk_msg_recvmsg(). A prior fix changed the last scatterlist check to sg_is_last(), but sockmap redirection without stream_parser, stream_verdict, or skb_verdict did not mark the scatterlist end. The stable fixes restore checking against msg_rx->sg.end to avoid a NULL pointer dereference in the TCP BPF receive path.

Likely exposure

Exposure appears limited to Linux kernels containing the faulty skmsg change and reachable BPF sockmap redirection receive paths. The source bundle names Linux kernel versions 5.15.61 and 5.19.2 and several commits, but it does not provide complete distribution package mapping.

Exploitation context

The bundle marks KEV as false and provides no cited evidence of active exploitation. It includes a kernel crash trace through recvfrom and tcp_bpf_recvmsg, but does not establish remote reachability, required privileges, or a public exploit.

Researcher notes

Key uncertainty is reachability. The sources describe the faulty end-of-scatterlist condition and fix, but not a complete trigger model, privilege boundary, or distro-specific affected ranges. Validate against exact kernel source packages rather than upstream version numbers alone.

Mitigation direction

  • Check Linux vendor advisories for your exact distribution kernel package.
  • Prioritize kernel updates that include the referenced stable fixes.
  • Inventory systems using eBPF, sockmap, or TCP BPF functionality.
  • Apply normal kernel patch maintenance for internet-facing and multi-tenant Linux hosts.

Validation and detection

  • Compare running kernel builds against vendor advisories for CVE-2022-49973.
  • Check whether deployed kernels include the referenced stable commits.
  • Identify workloads using BPF sockmap or TCP BPF receive paths.
  • Review crash logs for NULL pointer dereferences in tcp_bpf_recvmsg or sk_msg_recvmsg.
Prepared
Confidence
medium
Sources
5

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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CVE-2022-49973 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

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.

0CVSS vectors
3Timeline events
0ADP providers
4Source links

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux293c53b7dbf9073cbcc488f938bc053ff4caeec0, 1295dae30f30c3daa03005ed8958d44b17f037fd, 9974d37ea75f01b47d16072b5dad305bd8d23fcc, 4674c0da448b546e390a981b819cd4af5cb16cf9unaffected
LinuxLinux5.15.61, 5.19.2unaffected
Weakness

CWE details

No CWE listed

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