CVE-2026-63939

Exploitation

Not assessed. CISA has not published an exploitation assessment for this record, and it is not in the KEV catalog. That is an absence of assessment, not a finding of no risk.

SSVC decision

Not assessed by CISA

EPSS probability

0.19% probability of exploitation activity in the next 30 days.

EPSS percentile

Ranks above 9.2% of scored records. A rank, not a probability.

NVD base score

9.3 (CVSS v3.x), scored by the NVD independently of the CNA.

NVD CVSS vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

NVD analysis status

Awaiting Analysis. NVD last modified this record on 2026-07-27.

Red Hat severity

Important. Red Hat's rating for its own products, not a CVSS rating.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

Published

2026-07-19 14:55Z1 MO AGO

Last updated

2026-08-05 12:37Z1 MO AGO

Reserved

2026-07-19

Assigning CNA

Linux

Record state

PUBLISHED

Severity

Critical (CVSS 9.3)

CNA CVSS vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Weaknesses

• CWE-131Incorrect Calculation of Buffer SizeBase

Data version

5.2

Document digest

829fa65a951b7fd5208134042d41c860c27f41b7b873c7654dc414df6f2344e6

• git.kernel.orghttps://git.kernel.org/stable/c/6ca9400d36005ffdca25f80186bea781c7e1dc4c
• git.kernel.orghttps://git.kernel.org/stable/c/9f0a9e780f02c02d025a190f1885e1d1d73b87bd
• git.kernel.orghttps://git.kernel.org/stable/c/6644565527c4c5f507088b1c9ddf72de47790b68
• git.kernel.orghttps://git.kernel.org/stable/c/5867d7e202e09f037cefe77f7af4413c7c0fa088