Vulnerability Database

374,584

Total vulnerabilities in the database

CVE-2025-39967 — linux / linux_kernel

Integer Overflow or Wraparound

In the Linux kernel, the following vulnerability has been resolved:

fbcon: fix integer overflow in fbcon_do_set_font

Fix integer overflow vulnerabilities in fbcon_do_set_font() where font size calculations could overflow when handling user-controlled font parameters.

The vulnerabilities occur when:

  1. CALC_FONTSZ(h, pitch, charcount) performs h * pith * charcount multiplication with user-controlled values that can overflow.
  2. FONT_EXTRA_WORDS * sizeof(int) + size addition can also overflow
  3. This results in smaller allocations than expected, leading to buffer overflows during font data copying.

Add explicit overflow checking using check_mul_overflow() and check_add_overflow() kernel helpers to safety validate all size calculations before allocation.

  • Published: Oct 15, 2025
  • Updated: Feb 28, 2026
  • CVE: CVE-2025-39967
  • Severity: High
  • Exploit:
  • CISA KEV:

CVSS v3:

  • Severity: High
  • Score: 7.8
  • AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CWEs:

Software From Fixed in
linux / linux_kernel 4.4.235 4.5
linux / linux_kernel 4.9.235 4.10
linux / linux_kernel 4.14.196 4.15
linux / linux_kernel 4.19.143 4.20
linux / linux_kernel 5.4.62 5.4.300
linux / linux_kernel 5.8.6 5.9
linux / linux_kernel 5.9.1 5.10.245
linux / linux_kernel 5.11 5.15.194
linux / linux_kernel 5.16 6.1.155
linux / linux_kernel 6.2 6.6.109
linux / linux_kernel 6.7 6.12.50
linux / linux_kernel 6.13 6.16.10
linux / linux_kernel 5.9 5.9.x
linux / linux_kernel 5.9-rc3 5.9-rc3.x
linux / linux_kernel 5.9-rc4 5.9-rc4.x
linux / linux_kernel 5.9-rc5 5.9-rc5.x
linux / linux_kernel 5.9-rc6 5.9-rc6.x
linux / linux_kernel 5.9-rc7 5.9-rc7.x
linux / linux_kernel 5.9-rc8 5.9-rc8.x
linux / linux_kernel 6.17-rc1 6.17-rc1.x
linux / linux_kernel 6.17-rc2 6.17-rc2.x
linux / linux_kernel 6.17-rc3 6.17-rc3.x
linux / linux_kernel 6.17-rc4 6.17-rc4.x
linux / linux_kernel 6.17-rc5 6.17-rc5.x
linux / linux_kernel 6.17-rc6 6.17-rc6.x
linux / linux_kernel 6.17-rc7 6.17-rc7.x

Frequently Asked Questions

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.

Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.

Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.

SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.