CVE-2025-39967
HighCVSS 7.8Exploitation Probability (EPSS)
Low risk6th percentile - higher than 6% of all known CVEs
Summary
In the Linux kernel, the fbcon driver has an integer overflow vulnerability in the fbcon_do_set_font function. Font size calculations can overflow with user-controlled parameters, leading to undersized allocations and buffer overflow.
Risk Assessment
Risk of buffer overflow when setting console font, which could lead to system crash or potential code execution. An attacker could exploit this for privilege escalation.
Recommendation
Apply the Linux kernel patch that adds overflow checking using check_mul_overflow and check_add_overflow. Update the system to a kernel version containing the fix.
Other vulnerabilities in Linux kernel
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In the Linux kernel XFS filesystem, during directory tree repair, a self-referential directory may be detected. In such a case, the repair code attempts to lock the same inode twice (double iolock/ilock), leading to a deadlock. The fix detects this corner case and handles it appropriately.
- CVE-2026-80533Unknown
In the Linux kernel XFS filesystem, during AGI repair, the function xrep_iunlink_walk_ondisk_bucket may attempt to use the pointer sc->sa.agi_bp, which can be null if the buffer verifier fails. The fix uses ragi->agi_bp instead, which skips verifier checks, to avoid walking off the end of memory.
Original NVD description (English source)
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.