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CVE Record

CVE-2025-37920: xsk: Fix race condition in AF_XDP generic RX path

In the Linux kernel, the following vulnerability has been resolved: xsk: Fix race condition in AF_XDP generic RX path Move rx_lock from xsk_socket to xsk_buff_pool. Fix synchronization for shared umem mode in generic RX path where multiple sockets share single xsk_buff_pool. RX queue is exclusive to xsk_socket, while FILL queue can be shared between multiple sockets. This could result in race condition where two CPU cores access RX path of two different sockets sharing the same umem. Protect both queues by acquiring spinlock in shared xsk_buff_pool. Lock contention may be minimized in the future by some per-thread FQ buffering. It's safe and necessary to move spin_lock_bh(rx_lock) after xsk_rcv_check(): * xs->pool and spinlock_init is synchronized by xsk_bind() -> xsk_is_bound() memory barriers. * xsk_rcv_check() may return true at the moment of xsk_release() or xsk_unbind_dev(), however this will not cause any data races or race conditions. xsk_unbind_dev() removes xdp socket from all maps and waits for completion of all outstanding rx operations. Packets in RX path will either complete safely or drop.

HighCVSS 7.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A Linux kernel race condition can occur when multiple AF_XDP sockets on different CPU cores share one UMEM buffer pool in the generic receive path. Incorrect synchronization may compromise confidentiality, integrity, and availability. Exploitation requires local access and a specific AF_XDP configuration, so exposure is narrower than a remotely reachable kernel flaw.

Executive priority

Treat this as a high-priority targeted kernel update for AF_XDP packet-processing and multi-user systems. It is not presented as an internet-wide remote emergency, but potentially severe impact and low local attack complexity justify prompt inventory, vendor verification, and scheduled remediation.

Technical view

The RX queue belongs to an individual XDP socket, but the FILL queue may be shared through one xsk_buff_pool. The previous socket-level lock did not safely coordinate concurrent receive processing across shared-UMEM sockets. The fix moves the receive lock into the shared pool and protects both queues with a spinlock.

Likely exposure

Potential exposure exists on affected Linux kernels where AF_XDP uses the generic RX path and multiple sockets share one UMEM pool. The supplied affected-version data identifies several kernel lines but is irregular, so organizations should verify their exact distribution build against vendor guidance and the cited stable fixes.

Exploitation context

The CVSS vector describes local, low-complexity exploitation requiring low privileges and no user interaction, with potentially high confidentiality, integrity, and availability impact. The source bundle does not establish a specific resulting primitive or successful public exploitation. This CVE is not identified as being in CISA KEV by the supplied data.

Researcher notes

The vulnerable condition is concurrent generic receive processing by sockets sharing an xsk_buff_pool. The fix relocates rx_lock from xsk_socket to the shared pool and acquires it after xsk_rcv_check(). The bundle does not provide a CWE, detailed corruption outcome, proof of concept, or clear conventional version ranges; avoid inferring these.

Mitigation direction

  • Update to a vendor-supported kernel build containing the applicable cited stable fix.
  • Consult the Linux distribution vendor to map the fix to packaged kernel versions.
  • Prioritize affected systems that provide AF_XDP-based networking or packet processing.
  • Restrict unnecessary local access while affected systems await maintenance.

Validation and detection

  • Record the running kernel version and compare it with distribution-specific CVE guidance.
  • Identify systems using AF_XDP generic RX with shared UMEM across multiple sockets.
  • Confirm the applicable stable fix is present in the deployed kernel source or package.
  • After maintenance, verify the updated kernel is actually running.
Prepared
Confidence
medium
Sources
7

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.

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CVE-2025-37920 mapping review

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.8 (3.1)
Known Exploited
No
Published

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

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
0ADP providers
6Source links

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
7.8CVSS 3.1HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H1.85.9Linux

Vulnerability scoring details

Base CVSS 3.1 score

7.8High
CVSS 3.1 vector shape for CVE-2025-37920Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

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.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxbf0bdd1343efbbf65b4d53aef1fce14acbd79d50, bf0bdd1343efbbf65b4d53aef1fce14acbd79d50, bf0bdd1343efbbf65b4d53aef1fce14acbd79d50, bf0bdd1343efbbf65b4d53aef1fce14acbd79d50, bf0bdd1343efbbf65b4d53aef1fce14acbd79d50, fd7c22ba7a0ad898b9ecf77dd53f5ccc48492e35, 8a090e3b73eaffe18e08ccc3fb5abecf6b0a9781, 5.1.20, 5.2.3unaffected
LinuxLinux5.3, 0, 6.1.164, 6.6.123, 6.12.28, 6.14.6, 6.15affected
Weakness

CWE details

No CWE listed

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