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NVD / CVE Program· CNA Linux

CVE-2025-38524: rxrpc: Fix recv-recv race of completed call

Noroxi assessment

Priority: Monitor (action score 18/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.29% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. Special conditions such as timing or configuration are required.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: Linux Linux 4aed0eeca58e26d752bb08b293b8dc75c6820b23, 6c75a97a32a5fa2060c3dd30207e63b6914b606d, 7692bde890061797f3dece0148d7859e85c55778; azl3 kernel 6.6.96.2-2 on Azure Linux 3.0 6.6.104.2-1; cbl2 kernel 5.15.202.1-1 on CBL-Mariner 2.0 Release Notes.
  • Severity is disputed: the assigning authority (CNA) scores it 7.5, NVD 4.7.

Low priority for now. Upgrade to Linux Linux 4aed0eeca58e26d752bb08b293b8dc75c6820b23, 6c75a97a32a5fa2060c3dd30207e63b6914b606d, 7692bde890061797f3dece0148d7859e85c55778; azl3 kernel 6.6.96.2-2 on Azure Linux 3.0 6.6.104.2-1; cbl2 kernel 5.15.202.1-1 on CBL-Mariner 2.0 Release Notes or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: rxrpc: Fix recv-recv race of completed call If a call receives an event (such as incoming data), the call gets placed on the socket's queue and a thread in recvmsg can be awakened to go and process it. Once the thread has picked up the call off of the queue, further events will cause it to be requeued, and once the socket lock is dropped (recvmsg uses call->user_mutex to allow the socket to be used in parallel), a second thread can come in and its recvmsg can pop the call off the socket queue again. In such a case, the first thread will be receiving stuff from the call and the second thread will be blocked on call->user_mutex. The first thread can, at this point, process both the event that it picked call for and the event that the second thread picked the call for and may see the call terminate - in which case the call will be "released", decoupling the call from the user call ID assigned to it (RXRPC_USER_CALL_ID in the control message). The first thread will return okay, but then the second thread will wake up holding the user_mutex and, if it sees that the call has been released by the first thread, it will BUG thusly: kernel BUG at net/rxrpc/recvmsg.c:474! Fix this by just dequeuing the call and ignoring it if it is seen to be already released. We can't tell userspace about it anyway as the user call ID has become stale.

MediumCVSS 4.7 · v3.1—No exploit Fix available
Published
Aug 16, 2025
Updated
Oct 30, 2026
EPSS
0.2% · 22th percentile

Report tools

JSON

Action score

18

Monitor

Low priority for now.

CVSS
18 / 40 · 4.7 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
4.7
CNA · Linux
7.5
2.8 point gap

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2025-38524

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel4.9 and later · before 6.6.100
  • linux linux kernel6.7 and later · before 6.12.40
  • linux linux kernel6.13 and later · before 6.15.8
  • linux linux kernel6.16

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 4.9affected
    • 248f219cb8bcbfbd7f132752d44afa2df7c241d1 and later · before 4aed0eeca58e26d752bb08b293b8dc75c6820b23affected · git
    • 248f219cb8bcbfbd7f132752d44afa2df7c241d1 and later · before cb720b068b18fb39c96980eb3c13f09427512be7affected · git
    • 248f219cb8bcbfbd7f132752d44afa2df7c241d1 and later · before 7692bde890061797f3dece0148d7859e85c55778affected · git
    • 248f219cb8bcbfbd7f132752d44afa2df7c241d1 and later · before 839fe96c15209dc2255c064bb44b636efe04f032affected · git
    • 248f219cb8bcbfbd7f132752d44afa2df7c241d1 and later · before 6c75a97a32a5fa2060c3dd30207e63b6914b606daffected · git
    • 248f219cb8bcbfbd7f132752d44afa2df7c241d1 and later · before 962fb1f651c2cf2083e0c3ef53ba69e3b96d3fbcaffected · git
    • before 4.9not affected · semver
    • 5.10.266 and later · up to and including 5.10.*not affected · semver
    • 6.1.191 and later · up to and including 6.1.*not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxfrom 0—
Debian:13linuxbefore 6.12.41-16.12.41-1
Debian:14linuxbefore 6.16.3-16.16.3-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2025-38512Aug 16, 2025 · wifi: prevent A-MSDU attacks in mesh networks
    31Monitor
  • ← EarlierCVE-2025-38514Aug 16, 2025 · rxrpc: Fix oops due to non-existence of prealloc backlog struct
    22Monitor
  • Later →CVE-2025-38526Aug 16, 2025 · ice: add NULL check in eswitch lag check
    22Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux4aed0eeca58e26d752bb08b293b8dc75c6820b23Vendor (CNA)
Linux Linux6c75a97a32a5fa2060c3dd30207e63b6914b606dVendor (CNA)
Linux Linux7692bde890061797f3dece0148d7859e85c55778Vendor (CNA)
Linux Linux839fe96c15209dc2255c064bb44b636efe04f032Vendor (CNA)
Linux Linux962fb1f651c2cf2083e0c3ef53ba69e3b96d3fbcVendor (CNA)
Linux Linuxcb720b068b18fb39c96980eb3c13f09427512be7Vendor (CNA)
azl3 kernel 6.6.96.2-2 on Azure Linux 3.06.6.104.2-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
cbl2 kernel 5.15.202.1-1 on CBL-Mariner 2.0Release NotesMicrosoft (MSRC)
debian:linux6.12.41-1 · Debian:13Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
High
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-362 · Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

CVSS vector

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

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. SSVC exploitation— → none
  2. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (5 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records