CVE-2021-46905: net: hso: fix NULL-deref on disconnect regression
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: 0.26% (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 0c71d4c89559f72cec2592d078681a843bce570e, 0f000005da31f6947f843ce6b3e3a960540c6e00, 24b699bea7553fc0b98dad9d864befb6005ac7f1.
- Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).
Low priority for now. Upgrade to Linux Linux 0c71d4c89559f72cec2592d078681a843bce570e, 0f000005da31f6947f843ce6b3e3a960540c6e00, 24b699bea7553fc0b98dad9d864befb6005ac7f1 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: net: hso: fix NULL-deref on disconnect regression Commit 8a12f8836145 ("net: hso: fix null-ptr-deref during tty device unregistration") fixed the racy minor allocation reported by syzbot, but introduced an unconditional NULL-pointer dereference on every disconnect instead. Specifically, the serial device table must no longer be accessed after the minor has been released by hso_serial_tty_unregister().
- Published
- Feb 26, 2024
- Updated
- Jun 17, 2026
- EPSS
- 0.2% · 17th percentile
- CWE
- CWE-476
Report tools
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.
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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.
We use this product, ask for helpAffected 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.
| Vendor | Product | CPE |
|---|---|---|
| linux | linux kernel | cpe:2.3:o:linux:linux_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 4.19.189
- linux linux kernel4.20.0 and later · before 5.4.115
- linux linux kernel5.5.0 and later · before 5.10.33
- linux linux kernel5.11.0 and later · before 5.11.17
- linux linux kernel5.12
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
- 5.12affected
- a462067d7c8e6953a733bf5ade8db947b1bb5449 and later · before 5871761c5f0f20d6e98bf3b6bd7486d857589554affected · git
- 145c89c441d27696961752bf51b323f347601bee and later · before 0c71d4c89559f72cec2592d078681a843bce570eaffected · git
- caf5ac93b3b5d5fac032fc11fbea680e115421b4 and later · before 24b699bea7553fc0b98dad9d864befb6005ac7f1affected · git
- 92028d7a31e55d53e41cff679156b9432cffcb36 and later · before 5c17cfe155d21954b4c7e2a78fa771cebcd86725affected · git
- 4a2933c88399c0ebc738db39bbce3ae89786d723 and later · before d7fad2ce15bdbbd0fec3ebe999fd7cab2267f53eaffected · git
- dc195928d7e4ec7b5cfc6cd10dc4c8d87a7c72ac and later · before 90642ee9eb581a13569b1c0bd57e85d962215273affected · git
- 388d05f70f1ee0cac4a2068fd295072f1a44152a and later · before 0f000005da31f6947f843ce6b3e3a960540c6e00affected · git
- 8a12f8836145ffe37e9c8733dce18c22fb668b66 and later · before 41c44e1f3112d7265dae522c026399b2a42d19efaffected · git
- 8a12f8836145ffe37e9c8733dce18c22fb668b66 and later · before 2ad5692db72874f02b9ad551d26345437ea4f7f3affected · git
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| SUSE:Linux Enterprise High Availability Extension 12 SP5 | kernel-default | before 4.12.14-122.216.1 | 4.12.14-122.216.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSS | kernel-default-base | before 5.3.18-150200.24.183.1.150200.9.93.2 | 5.3.18-150200.24.183.1.150200.9.93.2 |
| SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSS | kernel-docs | before 5.3.18-150200.24.183.1 | 5.3.18-150200.24.183.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSS | kernel-obs-build | before 5.3.18-150200.24.183.1 | 5.3.18-150200.24.183.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSS | kernel-preempt | before 5.3.18-150200.24.183.1 | 5.3.18-150200.24.183.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSS | kernel-source | before 5.3.18-150200.24.183.1 | 5.3.18-150200.24.183.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSS | kernel-syms | before 5.3.18-150200.24.183.1 | 5.3.18-150200.24.183.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | kernel-64kb | before 5.3.18-150300.59.153.2 | 5.3.18-150300.59.153.2 |
| SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | kernel-default-base | before 5.3.18-150300.59.153.2.150300.18.90.2 | 5.3.18-150300.59.153.2.150300.18.90.2 |
| SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | kernel-docs | before 5.3.18-150300.59.153.2 | 5.3.18-150300.59.153.2 |
| SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | kernel-obs-build | before 5.3.18-150300.59.153.2 | 5.3.18-150300.59.153.2 |
| SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | kernel-preempt | before 5.3.18-150300.59.153.2 | 5.3.18-150300.59.153.2 |
| SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | kernel-source | before 5.3.18-150300.59.153.2 | 5.3.18-150300.59.153.2 |
| SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | kernel-syms | before 5.3.18-150300.59.153.1 | 5.3.18-150300.59.153.1 |
| SUSE:Linux Enterprise Live Patching 12 SP5 | kgraft-patch-SLE12-SP5_Update_56 | before 1-8.3.1 | 1-8.3.1 |
| SUSE:Linux Enterprise Live Patching 15 SP2 | kernel-default | before 5.3.18-150200.24.183.1 | 5.3.18-150200.24.183.1 |
| SUSE:Linux Enterprise Live Patching 15 SP2 | kernel-livepatch-SLE15-SP2_Update_46 | before 1-150200.5.3.2 | 1-150200.5.3.2 |
| SUSE:Linux Enterprise Live Patching 15 SP3 | kernel-default | before 5.3.18-150300.59.153.2 | 5.3.18-150300.59.153.2 |
| SUSE:Linux Enterprise Live Patching 15 SP3 | kernel-livepatch-SLE15-SP3_Update_42 | before 1-150300.7.3.2 | 1-150300.7.3.2 |
| SUSE:Linux Enterprise Micro 5.1 | kernel-rt | before 5.3.18-150300.161.1 | 5.3.18-150300.161.1 |
| SUSE:Linux Enterprise Micro 5.1 | kernel-source-rt | before 5.3.18-150300.161.1 | 5.3.18-150300.161.1 |
| SUSE:Linux Enterprise Real Time 12 SP5 | kernel-rt | before 4.12.14-10.182.1 | 4.12.14-10.182.1 |
| SUSE:Linux Enterprise Real Time 12 SP5 | kernel-rt_debug | before 4.12.14-10.182.1 | 4.12.14-10.182.1 |
| SUSE:Linux Enterprise Real Time 12 SP5 | kernel-source-rt | before 4.12.14-10.182.1 | 4.12.14-10.182.1 |
+15
Same product
linux: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV90Now
- 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 KEV89Now
- CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV85Now
Published before and after this one in the same product
- ← EarlierCVE-2023-52464Feb 23, 2024 · EDAC/thunderx: Fix possible out-of-bounds string access31Monitor
- ← EarlierCVE-2021-46904Feb 26, 2024 · net: hso: fix null-ptr-deref during tty device unregistration22Monitor
- Later →CVE-2022-48626Feb 26, 2024 · moxart: fix potential use-after-free on remove path31Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| Linux Linux | 0c71d4c89559f72cec2592d078681a843bce570e | Vendor (CNA) |
| Linux Linux | 0f000005da31f6947f843ce6b3e3a960540c6e00 | Vendor (CNA) |
| Linux Linux | 24b699bea7553fc0b98dad9d864befb6005ac7f1 | Vendor (CNA) |
| Linux Linux | 2ad5692db72874f02b9ad551d26345437ea4f7f3 | Vendor (CNA) |
| Linux Linux | 4.19.189 | Vendor (CNA) |
| Linux Linux | 41c44e1f3112d7265dae522c026399b2a42d19ef | Vendor (CNA) |
| Linux Linux | 5.10.33 | Vendor (CNA) |
| Linux Linux | 5.11.17 | Vendor (CNA) |
| Linux Linux | 5.4.115 | Vendor (CNA) |
| Linux Linux | 5871761c5f0f20d6e98bf3b6bd7486d857589554 | Vendor (CNA) |
| Linux Linux | 5c17cfe155d21954b4c7e2a78fa771cebcd86725 | Vendor (CNA) |
| Linux Linux | 90642ee9eb581a13569b1c0bd57e85d962215273 | Vendor (CNA) |
| Linux Linux | d7fad2ce15bdbbd0fec3ebe999fd7cab2267f53e | Vendor (CNA) |
| suse:kernel-64kb | 5.3.18-150300.59.153.2 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | Package registry (OSV) |
| suse:kernel-default | 5.3.18-150300.59.153.2 · SUSE:Linux Enterprise Live Patching 15 SP3 | Package registry (OSV) |
| suse:kernel-default-base | 5.3.18-150300.59.153.2.150300.18.90.2 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | Package registry (OSV) |
| suse:kernel-docs | 5.3.18-150300.59.153.2 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | Package registry (OSV) |
| suse:kernel-livepatch-SLE15-SP3_Update_42 | 1-150300.7.3.2 · SUSE:Linux Enterprise Live Patching 15 SP3 | Package registry (OSV) |
| suse:kernel-obs-build | 5.3.18-150300.59.153.2 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | Package registry (OSV) |
| suse:kernel-preempt | 5.3.18-150300.59.153.2 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | Package registry (OSV) |
| suse:kernel-rt | 5.3.18-150300.161.1 · SUSE:Linux Enterprise Micro 5.1 | Package registry (OSV) |
| suse:kernel-source | 5.3.18-150300.59.153.2 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | Package registry (OSV) |
| suse:kernel-source-rt | 5.3.18-150300.161.1 · SUSE:Linux Enterprise Micro 5.1 | Package registry (OSV) |
| suse:kernel-syms | 5.3.18-150300.59.153.1 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | Package registry (OSV) |
| suse:kernel-zfcpdump | 5.3.18-150300.59.153.2 · SUSE:Linux Enterprise Server 15 SP3-LTSS | Package 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.
No history yet (it accumulates with the daily EPSS job).
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 researchersFinders, 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).
National notice (Türkiye Cybersecurity Directorate / USOM)
Official security notices citing this record; remediation advice is on the agency's page.
- TR-24-0131 · Feb 27, 2024(Linux Kernel Güncellemesi)
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-476 · NULL Pointer DereferenceCVSS 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.
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (8 more)Show less
- git.kernel.org/stable/c/0f000005da31f6947f843ce6b3e3a960540c6e00
- git.kernel.org/stable/c/24b699bea7553fc0b98dad9d864befb6005ac7f1
- git.kernel.org/stable/c/2ad5692db72874f02b9ad551d26345437ea4f7f3
- git.kernel.org/stable/c/41c44e1f3112d7265dae522c026399b2a42d19ef
- git.kernel.org/stable/c/5871761c5f0f20d6e98bf3b6bd7486d857589554
- git.kernel.org/stable/c/5c17cfe155d21954b4c7e2a78fa771cebcd86725
- git.kernel.org/stable/c/90642ee9eb581a13569b1c0bd57e85d962215273
- git.kernel.org/stable/c/d7fad2ce15bdbbd0fec3ebe999fd7cab2267f53e
Vendor advisories and official records. Exploit/PoC links are deliberately left out.