LiveActive security incident?Get immediate response
CVE Record

CVE-2026-43178: procfs: fix possible double mmput() in do_procmap_query()

In the Linux kernel, the following vulnerability has been resolved: procfs: fix possible double mmput() in do_procmap_query() When user provides incorrectly sized buffer for build ID for PROCMAP_QUERY we return with -ENAMETOOLONG error. After recent changes this condition happens later, after we unlocked mmap_lock/per-VMA lock and did mmput(), so original goto out is now wrong and will double-mmput() mm_struct. Fix by jumping further to clean up only vm_file and name_buf.

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

Security readout for executives and security teams

Plain-English summary

CVE-2026-43178 is a Linux kernel procfs flaw where a local user can trigger incorrect cleanup in process memory-map handling. The bug can release the same kernel memory-management object twice. Its CVSS score is high, but the provided sources do not show active exploitation.

Executive priority

Treat as a high-priority kernel patching item for systems where users, tenants, or workloads have local execution. It is less urgent than a remotely exploitable internet-facing issue, but shared Linux hosts should be remediated quickly because privilege boundaries depend on kernel correctness.

Technical view

In do_procmap_query(), an incorrectly sized PROCMAP_QUERY build ID buffer can return -ENAMETOOLONG after locks were released and mmput() already ran. The old goto path then calls mmput() again, causing a double release of mm_struct. CVSS rates local, low-complexity, low-privilege impact as high for confidentiality, integrity, and availability.

Likely exposure

Exposure is likely limited to Linux systems running affected kernel versions listed in the CVE data, including 6.19, 6.12.75, 6.18.16, 6.19.6, and 7.0 ranges as presented. Systems with vendor kernels may depend on backports, so package advisories matter more than upstream version strings alone.

Exploitation context

The provided evidence indicates local attack vector with low privileges and no user interaction. KEV is false, and no supplied source states active exploitation or public exploit availability. The issue requires access to make local kernel-facing procfs queries, not remote network access by itself.

Researcher notes

The key condition is the ENAMETOOLONG path after lock release and prior mmput(), followed by an outdated cleanup target that double-calls mmput(). Analysis should focus on affected procfs PROCMAP_QUERY behavior and vendor backport status, not only upstream kernel version labels.

Mitigation direction

  • Apply vendor kernel updates that include the referenced stable procfs fix.
  • Check Red Hat and distribution advisories for backported fixed packages.
  • Prioritize multi-user, container-hosting, and shared compute systems.
  • Reduce unnecessary local shell access until patched.
  • Reboot into the updated kernel after maintenance approval.

Validation and detection

  • Inventory running Linux kernel versions across servers and endpoints.
  • Compare versions against CVE affected and unaffected ranges.
  • Confirm vendor packages include the stable fix or backport.
  • Review Red Hat CVE, Bugzilla, and CSAF/VEX status.
  • Verify systems booted into the patched kernel after updates.
Prepared
Confidence
medium
Sources
9

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.

cwe · low confidence lookup

CWE-1341: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2026-43178 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.

2CVSS vectors
5Timeline events
1ADP providers
8Source links

CVSS vector scores

2 official scores

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
7CVSS 3.1HighCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H15.9redhat-SADP

Vulnerability scoring details

Base CVSS 3.1 score

7.8High
CVSS 3.1 vector shape for CVE-2026-43178Attack 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. ADP timelineredhat-SADP

    Reported to Red Hat.

  3. ADP timelineredhat-SADP

    Made public.

  4. CVE publishedCVE Program

    The CVE record was published.

  5. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

redhat-SADPkernel: procfs: fix possible double mmput() in do_procmap_query()
other:Red Hat severity ratingcvssV3_1
  • 2026-05-06T00:00:00.000Z: Reported to Red Hat.
  • 2026-05-06T00:00:00.000Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxb9b97e6aeb534315f9646b2090d1a5024c6a4e82, cbc03ce3e6ce7e21214c3f02218213574c1a2d08, b5cbacd7f86f4f62b8813688c8e73be94e8e1951, b5cbacd7f86f4f62b8813688c8e73be94e8e1951, 6.12.70, 6.18.10unaffected
LinuxLinux6.19, 0, 6.12.75, 6.18.16, 6.19.6, 7.0affected
Weakness

CWE details

CWE-1341

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

CWE-1341 · source CWE mapping

Multiple Releases of Same Resource or Handle

Multiple Releases of Same Resource or Handle represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs