5.5

CVE-2021-46905: net: hso: fix NULL-deref on disconnect regression

Modified
AliasesUBUNTU-CVE-2021-46905
Published 25-02-2024Last modified 23-05-2026

Vulnerability summary

CVE-2021-46905 is a medium (CVSS 5.5) NULL Pointer Dereference vulnerability in linux. EPSS estimates a 0.26% chance of exploitation in the next 30 days, higher than 17.9% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 5.5, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
5.5/10
010
Medium · v3.1 (NVD)
EPSS score
0.26%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 9 · Related 7
RHSA-2021:4140RHSA-2021:4356SUSE-SU-2024:0856-1SUSE-SU-2024:0857-1SUSE-SU-2024:0926-1SUSE-SU-2024:1643-1

Timeline

  1. 25-02-2024
    PublishedVulnerability first disclosed.
  2. 23-05-2026
    Last modifiedVulnerability information updated.

Description

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().

CVSS metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

0.26%

Chance of exploitation in the next 30 days

Percentile

18%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.26% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu84 products
  • linux< 4.15.0-147.151 | < 5.4.0-77.86
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-aws< 4.15.0-1106.113 | < 5.4.0-1051.53
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Linux2 products
  • linux≥ a462067d7c8e6953a733bf5ade8db947b1bb5449, < 5871761c5f0f20d6e98bf3b6bd7486d857589554 | ≥ 145c89c441d27696961752bf51b323f347601bee, < 0c71d4c89559f72cec2592d078681a843bce570e | ≥ caf5ac93b3b5d5fac032fc11fbea680e115421b4, < 24b699bea7553fc0b98dad9d864befb6005ac7f1 | ≥ 92028d7a31e55d53e41cff679156b9432cffcb36, < 5c17cfe155d21954b4c7e2a78fa771cebcd86725 | ≥ 4a2933c88399c0ebc738db39bbce3ae89786d723, < d7fad2ce15bdbbd0fec3ebe999fd7cab2267f53e | ≥ dc195928d7e4ec7b5cfc6cd10dc4c8d87a7c72ac, < 90642ee9eb581a13569b1c0bd57e85d962215273 | ≥ 388d05f70f1ee0cac4a2068fd295072f1a44152a, < 0f000005da31f6947f843ce6b3e3a960540c6e00 | ≥ 8a12f8836145ffe37e9c8733dce18c22fb668b66, < 41c44e1f3112d7265dae522c026399b2a42d19ef | ≥ 8a12f8836145ffe37e9c8733dce18c22fb668b66, < 2ad5692db72874f02b9ad551d26345437ea4f7f3 | ≥ 4.19.187, < 4.19.189 | ≥ 5.4.112, < 5.4.115 | ≥ 5.10.30, < 5.10.33 | ≥ 5.11.14, < 5.11.17 | 5.12
  • linux_kernelEOL< 4.19.189 | ≥ 4.20.0, < 5.4.115 | ≥ 5.5.0, < 5.10.33 | ≥ 5.11.0, < 5.11.17 | 5.12 | 5.12:rc1 | 5.12:rc2 | 5.12:rc3 | 5.12:rc4 | 5.12:rc5 | 5.12:rc6 | 5.12:rc7

2 vendors · 86 products

References

12 links
Show all 12 references