5.5

CVE-2021-47333: misc: alcor_pci: fix null-ptr-deref when there is no PCI bridge

Analyzed
AliasesUBUNTU-CVE-2021-47333DEBIAN-CVE-2021-47333
Published 21-05-2024Last modified 11-05-2026

Vulnerability summary

CVE-2021-47333 is a medium (CVSS 5.5) NULL Pointer Dereference vulnerability in linux. EPSS estimates a 0.24% chance of exploitation in the next 30 days, higher than 15% 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 (CVE.org)
EPSS score
0.24%
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 3 · Related 3
SUSE-SU-2024:2010-1SUSE-SU-2024:2183-1SUSE-SU-2024:2185-1

Timeline

  1. 21-05-2024
    PublishedVulnerability first disclosed.
  2. 11-05-2026
    Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: misc: alcor_pci: fix null-ptr-deref when there is no PCI bridge There is an issue with the ASPM(optional) capability checking function. A device might be attached to root complex directly, in this case, bus->self(bridge) will be NULL, thus priv->parent_pdev is NULL. Since alcor_pci_init_check_aspm(priv->parent_pdev) checks the PCI link's ASPM capability and populate parent_cap_off, which will be used later by alcor_pci_aspm_ctrl() to dynamically turn on/off device, what we can do here is to avoid checking the capability if we are on the root complex. This will make pdev_cap_off 0 and alcor_pci_aspm_ctrl() will simply return when bring called, effectively disable ASPM for the device. [ 1.246492] BUG: kernel NULL pointer dereference, address: 00000000000000c0 [ 1.248731] RIP: 0010:pci_read_config_byte+0x5/0x40 [ 1.253998] Call Trace: [ 1.254131] ? alcor_pci_find_cap_offset.isra.0+0x3a/0x100 [alcor_pci] [ 1.254476] alcor_pci_probe+0x169/0x2d5 [alcor_pci]

CVSS metrics

5 scores · 4 sources · 2 versions

EPSS trend

Probability

0.24%

Chance of exploitation in the next 30 days

Percentile

15%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.24% 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.

Ubuntu88 products
  • linuxAll versions (No fix recorded) | < 5.4.0-88.99
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-awsAll versions (No fix recorded) | < 5.4.0-1057.60
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Linux2 products
  • linux≥ 4f556bc04e3c0de2f5c69adc9e9f2bcefcad079d, < d2639ffdcad463b358b6bef8645ff81715daffcb | ≥ 4f556bc04e3c0de2f5c69adc9e9f2bcefcad079d, < 58f69684ba03e5b0e0a3ae844a845280c0f06309 | ≥ 4f556bc04e3c0de2f5c69adc9e9f2bcefcad079d, < 717cf5ae52322ddbdf3ac2c584b34c5970b0d174 | ≥ 4f556bc04e3c0de2f5c69adc9e9f2bcefcad079d, < 09d154990ca82d14aed2b72796f6c8845e2e605d | ≥ 4f556bc04e3c0de2f5c69adc9e9f2bcefcad079d, < 3ce3e45cc333da707d4d6eb433574b990bcc26f5 | 5.0
  • linux_kernel< 5.4.134 | ≥ 5.5, < 5.10.52 | ≥ 5.11, < 5.12.19 | ≥ 5.13, < 5.13.4
Debian1 product
  • linux< 5.14.6-1

3 vendors · 91 products

References

9 links