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NVD / CVE Program· CNA Linux

CVE-2021-46928: parisc: Clear stale IIR value on instruction access rights trap

MediumCVSS 5.5 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 22/100)

  • 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: 0.22% (FIRST EPSS).
  • 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.
  • Fixed version: Linux Linux 484730e5862f6b872dca13840bed40fd7c60fa26, d01e9ce1af6116f812491d3d3873d204f10ae0b8, e96373f0a5f484bc1e193f9951dcb3adf24bf3f7.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 484730e5862f6b872dca13840bed40fd7c60fa26, d01e9ce1af6116f812491d3d3873d204f10ae0b8, e96373f0a5f484bc1e193f9951dcb3adf24bf3f7 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: parisc: Clear stale IIR value on instruction access rights trap When a trap 7 (Instruction access rights) occurs, this means the CPU couldn't execute an instruction due to missing execute permissions on the memory region. In this case it seems the CPU didn't even fetched the instruction from memory and thus did not store it in the cr19 (IIR) register before calling the trap handler. So, the trap handler will find some random old stale value in cr19. This patch simply overwrites the stale IIR value with a constant magic "bad food" value (0xbaadf00d), in the hope people don't start to try to understand the various random IIR values in trap 7 dumps.

Published
Feb 27, 2024
Updated
Jun 17, 2026
EPSS
0.2% · 13th percentile

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

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-2021-46928

When you'll hear from us

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  • 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

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

    • 2.6.12affected
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before d01e9ce1af6116f812491d3d3873d204f10ae0b8affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before e96373f0a5f484bc1e193f9951dcb3adf24bf3f7affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 484730e5862f6b872dca13840bed40fd7c60fa26affected · git
    • before 2.6.12not affected · semver
    • 5.10.90 and later · up to and including 5.10.*not affected · semver
    • 5.15.13 and later · up to and including 5.15.*not affected · semver
    • 5.16 and laternot affected · original_commit_for_fix

Affected versions

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

  • linux linux kernelbefore 5.10.90
  • linux linux kernel5.11.0 and later · before 5.15.13

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 5.15.15-15.15.15-1

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-2021-46926Feb 27, 2024 · ALSA: hda: intel-sdw-acpi: harden detection of controller
    22Monitor
  • ← EarlierCVE-2021-46927Feb 27, 2024 · nitro_enclaves: Use get_user_pages_unlocked() call to handle mmap assert
    22Monitor
  • Later →CVE-2021-46929Feb 27, 2024 · sctp: use call_rcu to free endpoint
    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 Linux484730e5862f6b872dca13840bed40fd7c60fa26Vendor (CNA)
Linux Linuxd01e9ce1af6116f812491d3d3873d204f10ae0b8Vendor (CNA)
Linux Linuxe96373f0a5f484bc1e193f9951dcb3adf24bf3f7Vendor (CNA)
debian:linux5.15.15-1 · 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.

Variant candidates

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

  • CVE-2024-265846 days apartnet: tls: handle backlogging of crypto requests
    22Monitor
  • CVE-2022-4861947 days apartAn issue was discovered in drivers/input/input.c in the Linux kernel before 5.17.10.
    22Monitor
  • CVE-2022-4867366 days apartnet/smc: Fix possible access to freed memory in link clear
    22Monitor
  • CVE-2023-5090113 days apartKernel: kvm: svm: improper check in svm_set_x2apic_msr_interception allows direct access to host x2apic msrs
    22Monitor
  • CVE-2024-50001237 days apartnet/mlx5: Fix error path in multi-packet WQE transmit
    22Monitor
  • CVE-2024-50002237 days apartstatic_call: Handle module init failure correctly in static_call_del_module()
    22Monitor

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · public bounty program.

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

Weakness class (CWE)

CWE-755 · Improper Handling of Exceptional Conditions

CVSS vector

CVSS:3.1/AV:L/AC:L/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.

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

References

Show all references (2 more)

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

All records