How severe is CVE-2021-47649?

CVE-2021-47649 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-47649 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (14th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-47649?

CVE-2021-47649 affects Linux Linux Kernel. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-47649?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2021-47649 have an EU (EUVD) identifier?

Yes. CVE-2021-47649 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-34656.

When was CVE-2021-47649 published?

CVE-2021-47649 was published on 2025-02-26 and last updated on 2026-06-17.

CVE-2021-47649

CVE-2021-47649 is a medium-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: Medium (CVSS 3.x base score 5.5)
EPSS exploit prediction: 0% (14th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2021-34656
Affected product: Linux Linux Kernel
Published: 2025-02-26
Last modified: 2026-06-17

Description

In the Linux kernel, the following vulnerability has been resolved: udmabuf: validate ubuf->pagecount Syzbot has reported GPF in sg_alloc_append_table_from_pages(). The problem was in ubuf->pages == ZERO_PTR. ubuf->pagecount is calculated from arguments passed from user-space. If user creates udmabuf with list.size == 0 then ubuf->pagecount will be also equal to zero; it causes kmalloc_array() to return ZERO_PTR. Fix it by validating ubuf->pagecount before passing it to kmalloc_array().

Frequently asked questions

What is CVE-2021-47649?: In the Linux kernel, the following vulnerability has been resolved: udmabuf: validate ubuf->pagecount Syzbot has reported GPF in sg_alloc_append_table_from_pages(). The problem was in ubuf->pages == ZERO_PTR. ubuf->pagecount is calculated from arguments passed from user-space. If user creates udmabuf with list.size == 0 then ubuf->pagecount will be also equal to zero; it causes kmalloc_array() to return ZERO_PTR. Fix it by validating ubuf->pagecount before passing it to kmalloc_array().
How severe is CVE-2021-47649?: CVE-2021-47649 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-47649 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (14th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-47649?: CVE-2021-47649 affects Linux Linux Kernel. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-47649?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2021-47649 have an EU (EUVD) identifier?: Yes. CVE-2021-47649 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-34656.
When was CVE-2021-47649 published?: CVE-2021-47649 was published on 2025-02-26 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

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