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CVE-2021-47334· NVD / CVE Program· CNA Linux

misc/libmasm/module: Fix two use after free in ibmasm_init_one

In the Linux kernel, the following vulnerability has been resolved: misc/libmasm/module: Fix two use after free in ibmasm_init_one In ibmasm_init_one, it calls ibmasm_init_remote_input_dev(). Inside ibmasm_init_remote_input_dev, mouse_dev and keybd_dev are allocated by input_allocate_device(), and assigned to sp->remote.mouse_dev and sp->remote.keybd_dev respectively. In the err_free_devices error branch of ibmasm_init_one, mouse_dev and keybd_dev are freed by input_free_device(), and return error. Then the execution runs into error_send_message error branch of ibmasm_init_one, where ibmasm_free_remote_input_dev(sp) is called to unregister the freed sp->remote.mouse_dev and sp->remote.keybd_dev. My patch add a "error_init_remote" label to handle the error of ibmasm_init_remote_input_dev(), to avoid the uaf bugs.

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
May 21, 2024
Updated
Jun 17, 2026
EPSS
0.3% · 18th percentile
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Report tools

JSON

Action score

31

Monitor

Low priority for now.

CVSS
31 / 40 · 7.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.3%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Affected systems

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 kernelbefore 4.4.276
  • linux linux kernel4.5 and later · before 4.9.276
  • linux linux kernel4.10 and later · before 4.14.240
  • linux linux kernel4.15 and later · before 4.19.198
  • linux linux kernel4.20 and later · before 5.4.134
  • linux linux kernel5.5 and later · before 5.10.52
  • linux linux kernel5.11 and later · before 5.12.19
  • linux linux kernel5.13 and later · before 5.13.4

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

    • 2.6.16affected
    • 736ce43295682d060f2b93624b4a339f9af6aab1 and later · before 1512e7dc5eb08b7d92a12e2bfcd9cb8c4a1ec069affected · git
    • 736ce43295682d060f2b93624b4a339f9af6aab1 and later · before 29ba8e2ba89ee2862a26d91204dd5fe77ceee25aaffected · git
    • 736ce43295682d060f2b93624b4a339f9af6aab1 and later · before 5b06ca113bf197aab2ab61288f42506e0049fbabaffected · git
    • 736ce43295682d060f2b93624b4a339f9af6aab1 and later · before 481a76d4749ee3a27f902ba213fdcbb4bb39720eaffected · git
    • 736ce43295682d060f2b93624b4a339f9af6aab1 and later · before 38660031e80eaa6cc9370b031c180612f414b00daffected · git
    • 736ce43295682d060f2b93624b4a339f9af6aab1 and later · before b9c87ce3bc6331f82811a8cf8e930423c22523a3affected · git
    • 736ce43295682d060f2b93624b4a339f9af6aab1 and later · before ef1067d2baa847d53c9988510d99fb494de4d12caffected · git
    • 736ce43295682d060f2b93624b4a339f9af6aab1 and later · before a7268e8a227d5a4f0bd1584f556246b0224ab274affected · git
    • 736ce43295682d060f2b93624b4a339f9af6aab1 and later · before 7272b591c4cb9327c43443f67b8fbae7657dd9aeaffected · git

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 5.14.6-15.14.6-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

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    85Now
  • CVE-2016-5195Race condition in mm/gup.c in the Linux kernel 2.x through 4.x before 4.8.3 allows local users to gain privileges by leveraging incorrect haKEV
    83Now
  • CVE-2019-13272In the Linux kernel before 5.1.17, ptrace_link in kernel/ptrace.c mishandles the recording of the credentials of a process that wants to creKEV
    77This week
  • CVE-2013-6282The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the v6k and v7 ARM platforms do not validate certain addKEV
    77This week
  • CVE-2013-2094The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9 uses an incorrect integer data type, which allows loKEV
    77This week

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 Linux1512e7dc5eb08b7d92a12e2bfcd9cb8c4a1ec069Vendor (CNA)
Linux Linux29ba8e2ba89ee2862a26d91204dd5fe77ceee25aVendor (CNA)
Linux Linux38660031e80eaa6cc9370b031c180612f414b00dVendor (CNA)
Linux Linux481a76d4749ee3a27f902ba213fdcbb4bb39720eVendor (CNA)
Linux Linux5b06ca113bf197aab2ab61288f42506e0049fbabVendor (CNA)
Linux Linux7272b591c4cb9327c43443f67b8fbae7657dd9aeVendor (CNA)
Linux Linuxa7268e8a227d5a4f0bd1584f556246b0224ab274Vendor (CNA)
Linux Linuxb9c87ce3bc6331f82811a8cf8e930423c22523a3Vendor (CNA)
Linux Linuxef1067d2baa847d53c9988510d99fb494de4d12cVendor (CNA)
debian:linux5.14.6-1 · Debian:12Package 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.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

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.
  • No special conditions are required; it is repeatable.

If successful

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

Weakness class (CWE)

CWE-416 · Use After Free

CVSS vector

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

nvd-primary

Root cause

After a memory region is freed, another reference pointing to it is still used. By then, the same region may have been allocated for different data.

The bug in code

The whole CWE-416 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

c
free(dev->buf);/* ... another thread is still running ... */process(dev->buf);

Fixed

c
lock(&dev->lock);free(dev->buf);dev->buf = NULL;unlock(&dev->lock);

Attack context

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

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Noroxi analysis

No Noroxi analysis for this record yet

We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.

We use this product, ask for help

Change log

  1. Fix✗ → ✓

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

References

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

All records