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CVE Record

CVE-2024-26731: bpf, sockmap: Fix NULL pointer dereference in sk_psock_verdict_data_ready()

In the Linux kernel, the following vulnerability has been resolved: bpf, sockmap: Fix NULL pointer dereference in sk_psock_verdict_data_ready() syzbot reported the following NULL pointer dereference issue [1]: BUG: kernel NULL pointer dereference, address: 0000000000000000 [...] RIP: 0010:0x0 [...] Call Trace: <TASK> sk_psock_verdict_data_ready+0x232/0x340 net/core/skmsg.c:1230 unix_stream_sendmsg+0x9b4/0x1230 net/unix/af_unix.c:2293 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0x221/0x270 net/socket.c:745 ____sys_sendmsg+0x525/0x7d0 net/socket.c:2584 ___sys_sendmsg net/socket.c:2638 [inline] __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2667 do_syscall_64+0xf9/0x240 entry_SYSCALL_64_after_hwframe+0x6f/0x77 If sk_psock_verdict_data_ready() and sk_psock_stop_verdict() are called concurrently, psock->saved_data_ready can be NULL, causing the above issue. This patch fixes this issue by calling the appropriate data ready function using the sk_psock_data_ready() helper and protecting it from concurrency with sk->sk_callback_lock.

MediumCVSS 5.3Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2024-26731 is a Linux kernel flaw where a race in BPF sockmap verdict handling can crash kernel code through a NULL pointer dereference. The documented impact is limited availability loss, not data theft or integrity compromise. Treat it as a routine but real kernel patching priority.

Executive priority

Prioritize through normal kernel maintenance, with faster handling for critical or externally reachable Linux infrastructure. The evidence supports availability risk, not confirmed compromise risk. No active exploitation is cited in the provided sources.

Technical view

The issue is in sk_psock_verdict_data_ready(). Concurrent calls with sk_psock_stop_verdict() can leave psock->saved_data_ready NULL. The fix routes through sk_psock_data_ready() and protects callback handling with sk->sk_callback_lock. CVSS 3.1 is 5.3 with availability-only impact.

Likely exposure

Exposure is limited to Linux systems running affected kernel versions or downstream builds without the stable fix. The source bundle lists affected Linux versions including 6.4, 6.1.80, 6.6.19, 6.7.7, and 6.8. Distribution backports may change version-based assessment.

Exploitation context

The bundle does not show CISA KEV listing or public active exploitation. The CVSS vector says network attack complexity is low and no privileges or user interaction are required, but the documented technical detail is a kernel NULL dereference causing limited availability impact.

Researcher notes

This is a CWE-476 NULL pointer dereference in Linux BPF sockmap verdict callback handling. The interesting area is callback concurrency around saved_data_ready and sk_callback_lock. Evidence is strongest for root cause and fix, weaker for real-world exploitability.

Mitigation direction

  • Update to a vendor kernel containing the referenced stable fix commits.
  • Check distribution advisories for backported fixes for CVE-2024-26731.
  • Reboot systems after kernel update so the fixed kernel is active.
  • If patching is delayed, follow vendor guidance for supported mitigations.

Validation and detection

  • Inventory running Linux kernel versions across production and edge systems.
  • Confirm installed kernel packages reference CVE-2024-26731 or the stable commits.
  • Verify each host rebooted into the patched kernel after updating.
  • Review crash logs for matching sk_psock_verdict_data_ready NULL dereferences.
Prepared
Confidence
high
Sources
6

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

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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cwe · low confidence lookup

CWE-476: Exact CWE lookup

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cve · low confidence lookup

CVE-2024-26731 mapping review

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Vulnerability profileCVE Program record
Severity
Medium
CVSS
5.3 (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:L

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.

1CVSS vectors
3Timeline events
2ADP providers
5Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

CVSS vector scores

1 official score

We 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.

ScoreVersionSeverityVectorExploitImpactSource
5.3CVSS 3.1MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L3.91.4CISA-ADP

Vulnerability scoring details

Base CVSS 3.1 score

5.3Medium
CVSS 3.1 vector shape for CVE-2024-26731Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

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.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
cvssV3_1other:ssvc
CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxdd628fc697ee59b76bd3877c4bd13f07ccc3776f, 6df7f764cd3cf5a03a4a47b23be47e57e41fcd85, 6df7f764cd3cf5a03a4a47b23be47e57e41fcd85, 6df7f764cd3cf5a03a4a47b23be47e57e41fcd85, d3cbd7c571446a876aefd8320500300b2c951c58, 6.1.32, 6.3.6unaffected
LinuxLinux6.4, 0, 6.1.80, 6.6.19, 6.7.7, 6.8affected
Weakness

CWE details

CWE-476

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-476 · source CWE mapping

NULL Pointer Dereference

NULL Pointer Dereference represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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