High Memory corruption

CVE-2025-39967 — fbcon: fix integer overflow in fbcon_do_set_font

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 Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: Linux

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 0.2% (30-day exploitation probability)+1
Technical severity (high)+6

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

0.17%

ahead of 6% of scored CVEs · Oct 15, 2026

Affects

Linux

Linux and 1 more

CVSS base

7.8

High · 3 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation

None

none · proof-of-concept · active

Automatable

can an attacker script the kill-chain steps

Technical impact

Total

partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

Documented patch — git.kernel.org (NIST National Vulnerability Database)
Documented patch — git.kernel.org (NIST National Vulnerability Database)
Documented patch — git.kernel.org (NIST National Vulnerability Database)
Documented patch — git.kernel.org (NIST National Vulnerability Database)
Documented patch — git.kernel.org (NIST National Vulnerability Database)
Documented patch — git.kernel.org (NIST National Vulnerability Database)
Documented patch — git.kernel.org (NIST National Vulnerability Database)
Documented patch — git.kernel.org (NIST National Vulnerability Database)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Linux Linux, Linux Linux Kernel).
Apply the fixed version or the patch documented under Remediation.
Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Linux	Linux	version 5.9≥ 96e41fc29e8af5c5085fb8a79cab8d0d00bab86c and < 994bdc2d23c79087fbf7dcd9544454e8ebcef877≥ 39b3cffb8cf3111738ea993e2757ab382253d86a and < 9c8ec14075c5317edd6b242f1be8167aa1e4e333≥ 39b3cffb8cf3111738ea993e2757ab382253d86a and < b8a6e85328aeb9881531dbe89bcd2637a06c3c95≥ 39b3cffb8cf3111738ea993e2757ab382253d86a and < a6eb9f423b3db000aaedf83367b8539f6b72dcfc≥ 39b3cffb8cf3111738ea993e2757ab382253d86a and < adac90bb1aaf45ca66f9db8ac100be16750ace78≥ 39b3cffb8cf3111738ea993e2757ab382253d86a and < 4a4bac869560f943edbe3c2b032062f6673b13d3≥ 39b3cffb8cf3111738ea993e2757ab382253d86a and < c0c01f9aa08c8e10e10e8c9ebb5be01a4eff6eb7 and 12 more ≥ 39b3cffb8cf3111738ea993e2757ab382253d86a and < 1a194e6c8e1ee745e914b0b7f50fa86c89ed13feversion ae021a904ac82d9fc81c25329d3c465c5a7d5686version 451bffa366f2cc0e5314807cb847f31c0226efedversion 2c455e9c5865861f5ce09c5f596909495ed7657cversion 72f099805dbc907fbe8fa19bccdc31d3e2ee6e9eversion 34cf1aff169dc6dedad8d79da7bf1b4de2773dbc≥ 5.4.62 and < 5.4.300≥ 4.4.235 and < 4.5≥ 4.9.235 and < 4.10≥ 4.14.196 and < 4.15≥ 4.19.143 and < 4.20≥ 5.8.6 and < 5.9	Vulnerable	CVE Program (cve.org) e CISA ADP
Linux	Linux Kernel	version 6.17-rc5version 6.17-rc7version 6.17-rc6version 5.9≥ 4.9.235 and < 4.10≥ 4.14.196 and < 4.15≥ 4.19.143 and < 4.20≥ 5.4.62 and < 5.4.300 and 18 more ≥ 5.8.6 and < 5.9≥ 5.9.1 and < 5.10.245≥ 5.11 and < 5.15.194≥ 5.16 and < 6.1.155≥ 6.2 and < 6.6.109≥ 6.7 and < 6.12.50≥ 6.13 and < 6.16.10≥ 4.4.235 and < 4.5version 5.9-rc3version 5.9-rc4version 5.9-rc5version 5.9-rc6version 5.9-rc7version 5.9-rc8version 6.17-rc1version 6.17-rc2version 6.17-rc3version 6.17-rc4	Vulnerable	NIST National Vulnerability Database

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Local

Attack complexity

Low

Privileges required

Low

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
7.8	CVSS 3.1	High	1.8	5.9	416baaa9-dc9f-4396-8d5f-8c081fb06d67 via NIST National Vulnerability Database
7.8	CVSS 3.1	High	1.8	5.9	nvd@nist.gov via NIST National Vulnerability Database
7.8	CVSS 3.1	High	—	—	Linux via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H (score shown at the top: nvd@nist.gov)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-190 · Integer Overflow or Wraparound

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 15, 2026 · 3 reading(s) · max 0.17%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.

endpoint telemetry (EDR)crash dumps

Timeline

What happened to this CVE, newest first.

2026
Affected products added · linux/linux
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
SSVC assessment updated
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 13, 2026
Fix documented
Oct 13, 2026 · NIST National Vulnerability Database
CVSS changed · 7.8
Oct 13, 2026 · NIST National Vulnerability Database
Source status changed · → Modified
Oct 13, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 13, 2026 · NIST National Vulnerability Database
2025
CVE published
Oct 15, 2025 · Linux

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

8 on the record

git.kernel.org/stable/c/c0c01f9aa08c8e10e10e8c9ebb5be01a4eff6eb7
Patch, NIST National Vulnerability Database
git.kernel.org/stable/c/b8a6e85328aeb9881531dbe89bcd2637a06c3c95
Patch, NIST National Vulnerability Database
git.kernel.org/stable/c/1a194e6c8e1ee745e914b0b7f50fa86c89ed13fe
Patch, NIST National Vulnerability Database
git.kernel.org/stable/c/994bdc2d23c79087fbf7dcd9544454e8ebcef877
Patch, NIST National Vulnerability Database
git.kernel.org/stable/c/adac90bb1aaf45ca66f9db8ac100be16750ace78
Patch, NIST National Vulnerability Database
git.kernel.org/stable/c/a6eb9f423b3db000aaedf83367b8539f6b72dcfc
Patch, NIST National Vulnerability Database
git.kernel.org/stable/c/4a4bac869560f943edbe3c2b032062f6673b13d3
Patch, NIST National Vulnerability Database
git.kernel.org/stable/c/9c8ec14075c5317edd6b242f1be8167aa1e4e333
Patch, NIST National Vulnerability Database

Elsewhere on this site

Linux
every CVE for this vendor

Memory corruption
same class

CWE-190
other pages naming this weakness

Related CVEs (same products)

Critical CVE-2026-99999 ipv4: validate checksum_start before completing checksum 15h
Unknown CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 15h
Unknown CVE-2026-98431 RDMA/uverbs: Fix mmap_lock/disassociation_lock circular dependency 1d
Unknown CVE-2026-98430 RDMA/efa: Keep admin queues alive while IRQ is registered 1d
Unknown CVE-2026-98429 RDMA/efa: Keep EQ resources alive while IRQ is registered 1d
Unknown CVE-2026-98428 ALSA: usb: 6fire: Avoid embedded URBs 1d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2025-39967 is "fbcon: fix integer overflow in fbcon_do_set_font", rated High. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.8 describes technical severity. EPSS 0.17% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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