CVE Intelligence
Medium

CVE-2025-38544 — rxrpc: Fix bug due to prealloc collision

In the Linux kernel, the following vulnerability has been resolved: rxrpc: Fix bug due to prealloc collision When userspace is using AF_RXRPC to provide a server, it has to preallocate incoming calls and assign to them call IDs that will be used to thread related recvmsg() and sendmsg() together. The preallocated call IDs will automatically be attached to calls as they come in until the pool is empty. To the kernel, the call IDs are just arbitrary numbers, but userspace can use the call ID to hold a pointer to prepared structs. In any case, the user isn't permitted to create two calls with the same call ID (call IDs become available again when the call ends) and EBADSLT should result from sendmsg() if an attempt is made to preallocate a call with an in-use call ID. However, the cleanup in the error handling will trigger both assertions in rxrpc_cleanup_call() because the call isn't marked complete and isn't marked as having been released. Fix this by setting the call state in rxrpc_service_prealloc_one() and then marking it as being released before calling the cleanup function.

Published Aug 16, 2025 · Updated Oct 30, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: Linux

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 0.2% (30-day exploitation probability)+1
  • Technical severity (medium)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
0.15%
ahead of 5% of scored CVEs · Oct 30, 2026
Affects
Linux
Linux and 1 more
CVSS base
5.5
Medium · 2 source(s)

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

  • Documented patch — git.kernel.org (NIST National Vulnerability Database)
  • Documented patch — git.kernel.org (NIST National Vulnerability Database)
  • Documented patch — git.kernel.org (NIST National Vulnerability Database)
  • Documented patch — git.kernel.org (NIST National Vulnerability Database)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Linux Linux, Linux Linux Kernel).
  2. Apply the fixed version or the patch documented under Remediation.
  3. Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Linux Linux ≥ 00e907127e6f86d0f9b122d9b4347a8aa09a8b61 and < 3838acfc347b803b66a2c8eb510da1c489d44ca1≥ 00e907127e6f86d0f9b122d9b4347a8aa09a8b61 and < 432c5363cd6fe5a928bbc94524d28b05515684dd≥ 00e907127e6f86d0f9b122d9b4347a8aa09a8b61 and < 5385ad53793de2ab11e396bdcdaa65bb04b4dad6≥ 00e907127e6f86d0f9b122d9b4347a8aa09a8b61 and < d8ffb47a443919277cb093c3db1ec6c0a06880b1≥ 00e907127e6f86d0f9b122d9b4347a8aa09a8b61 and < 69e4186773c6445b258fb45b6e1df18df831ec45version 4.9 Vulnerable CVE Program (cve.org) e CISA ADP
Linux Linux Kernel ≥ 4.9 and < 6.6.99≥ 6.7 and < 6.12.39≥ 6.13 and < 6.15.7version 6.16-rc1version 6.16-rc2version 6.16-rc3version 6.16-rc4version 6.16-rc5 Vulnerable NIST National Vulnerability Database

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
5.5 CVSS 3.1 Medium 1.8 3.6 nvd@nist.gov via NIST National Vulnerability Database
5.5 CVSS 3.1 Medium — — GitHub, Inc. via GitHub Security Advisories
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H (score shown at the top: nvd@nist.gov)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-617

Other CVEs with this weakness →

EPSS over time FIRST

Oct 29, 2026 → Oct 30, 2026 · 2 reading(s) · max 0.15%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
endpoint telemetry (EDR)

Timeline

What happened to this CVE, newest first.

  • 2026
  • Affected products added · linux/linux
    Oct 30, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 30, 2026
  • Fix documented
    Oct 30, 2026 · NIST National Vulnerability Database
  • Affected products added · linux/linux kernel
    Oct 30, 2026 · NIST National Vulnerability Database
  • CVSS changed · 5.5
    Oct 30, 2026 · NIST National Vulnerability Database
  • Source status changed · → Modified
    Oct 30, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 30, 2026 · Alertas do Telegram
  • 2025
  • CVE published
    Aug 16, 2025 · Linux

Source activity

Repeated readings are counted rather than listed.

  • 2× References added · Oct 30, 2026 – Oct 30, 2026
  • 1× Official description updated · Oct 30, 2026 – Oct 30, 2026

References

7 on the record

Elsewhere on this site

Linux
every CVE for this vendor
CWE-617
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-99216 Drivers: hv: Don't reset VMBus connection state on error/exit paths 3d
  • CVE-2026-99215 power: supply: core: prevent unregistering a power supply while a callback runs 3d
  • CVE-2026-99207 scsi: target: Disable interrupts while holding delayed_cmd_lock 3d
  • CVE-2026-99208 drm/xe/oa: Zero OA buffer at allocation 3d
  • CVE-2026-99209 drm/xe: skip eviction of a BO with no resource 3d
  • CVE-2026-99210 accel/rocket: clear rdev on device init failure 3d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No CISA SSVC assessment.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2025-38544 is "rxrpc: Fix bug due to prealloc collision", rated Medium. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 5.5 describes technical severity. EPSS 0.15% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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