LiveActive security incident?Get immediate response
CVE Record

CVE-2026-23191: ALSA: aloop: Fix racy access at PCM trigger

In the Linux kernel, the following vulnerability has been resolved: ALSA: aloop: Fix racy access at PCM trigger The PCM trigger callback of aloop driver tries to check the PCM state and stop the stream of the tied substream in the corresponding cable. Since both check and stop operations are performed outside the cable lock, this may result in UAF when a program attempts to trigger frequently while opening/closing the tied stream, as spotted by fuzzers. For addressing the UAF, this patch changes two things: - It covers the most of code in loopback_check_format() with cable->lock spinlock, and add the proper NULL checks. This avoids already some racy accesses. - In addition, now we try to check the state of the capture PCM stream that may be stopped in this function, which was the major pain point leading to UAF.

HighCVSS 7.8Not KEV-listedUpdated
Discuss exposureBack to CVEs
Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2026-23191 is a Linux kernel flaw in the ALSA aloop audio loopback driver. A local user could trigger a race condition that may cause use-after-free memory corruption, with high confidentiality, integrity, and availability impact according to CVSS 7.8.

Executive priority

Treat as high priority for multi-user Linux fleets, workstations, and systems exposing local accounts or workloads. It is not described as remotely exploitable, but kernel memory corruption can have severe business impact if local access is available.

Technical view

The aloop PCM trigger path checked PCM state and stopped a tied substream outside the cable lock. Fuzzing found that repeated triggering while the tied stream opened or closed could race into use-after-free. Stable fixes add locking, NULL checks, and capture-stream state validation.

Likely exposure

Exposure is likely limited to Linux systems running affected kernels where the ALSA aloop driver is present and reachable by local users. The supplied version data is broad and should be reconciled with distribution kernel backports.

Exploitation context

The CVSS vector is local, low complexity, low privilege, and no user interaction. The source bundle does not identify public exploitation, exploit code, or CISA KEV listing, so active exploitation is not established.

Researcher notes

Focus review on aloop PCM trigger handling, tied substream lifecycle, cable locking, and NULL/state checks. Evidence supports a fuzz-discovered race-to-UAF fixed in stable commits; affected-version granularity is incomplete without vendor-specific kernel package mapping.

Mitigation direction

  • Apply vendor kernel updates that include the referenced stable aloop fixes.
  • Prioritize shared Linux systems and environments with untrusted local users.
  • Check Linux distribution advisories for backported fixed kernel packages.
  • If patching is delayed, review vendor guidance for temporary exposure reduction.

Validation and detection

  • Identify hosts running Linux kernels in the potentially affected version range.
  • Confirm whether the ALSA aloop driver is present or loaded on those hosts.
  • Map installed kernel packages to vendor advisories and fixed build numbers.
  • Verify remediation by confirming the deployed kernel includes the stable fix commits.
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

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

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cve · low confidence lookup

CVE-2026-23191 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
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
4Source 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-2026-23191Attack 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
LinuxLinuxb1c73fc8e697eb73e23603e465e9af2711ed4183, b1c73fc8e697eb73e23603e465e9af2711ed4183, b1c73fc8e697eb73e23603e465e9af2711ed4183unaffected
LinuxLinux2.6.37, 0, 6.12.70, 6.18.10, 6.19affected
Weakness

CWE details

No CWE listed

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