High Insecure deserialization

CVE-2025-15276 — FontForge SFD File Parsing Deserialization of Untrusted Data Remote Code Execution Vulnerability

FontForge SFD File Parsing Deserialization of Untrusted Data Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of FontForge. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the parsing of SFD files. The issue results from the lack of proper validation of user-supplied data, which can result in deserialization of untrusted data. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-28198.

Published Dec 31, 2025 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: zdi

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 0.4% (30-day exploitation probability)+4
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

0.35%

ahead of 27% of scored CVEs · Oct 14, 2026

Affects

Fontforge

CVSS base

7.8

High · 2 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.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

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 (Fontforge Fontforge).
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Exploitation requires user interaction: tighten email/web filtering and warn affected users.
Search available logs for exploit probes matching the vulnerability class (insecure deserialization), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Fontforge	Fontforge	version 20251009	Vulnerable	NIST National Vulnerability Database
Fontforge	Fontforge	version 836f4e11e4cb890353393b36c0465ef445e0c4d4	Vulnerable	CVE Program (cve.org) e CISA ADP

Attack characteristics

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

Attack vector

Local

Attack complexity

Low

Privileges required

None

User interaction

Required

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 3.0	High	1.8	5.9	zdi-disclosures@trendmicro.com via NIST National Vulnerability Database
7.8	CVSS 3.0	High	—	—	zdi via CVE Program (cve.org) e CISA ADP

CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H (score shown at the top: zdi-disclosures@trendmicro.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-502 · Deserialization of Untrusted Data

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.35%

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.
Monitor serialized objects in requests and unexpected processes spawned by the runtime.

endpoint telemetry (EDR)application logs

Timeline

What happened to this CVE, newest first.

2026
Affected products added · fontforge/fontforge
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
CVSS changed · 7.8
Oct 13, 2026 · NIST National Vulnerability Database
Source status changed · → Analyzed
Oct 13, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 13, 2026 · NIST National Vulnerability Database
2025
CVE published
Dec 31, 2025 · zdi

Source activity

Repeated readings are counted rather than listed.

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

References

1 on the record

www.zerodayinitiative.com/advisories/ZDI-25-1187/
Third Party Advisory, x_research-advisory, NIST National Vulnerability Database

Elsewhere on this site

Fontforge
every CVE for this vendor

Insecure deserialization
same class

CWE-502
other pages naming this weakness

Related CVEs (same products)

High CVE-2025-15277 FontForge GUtils SGI File Parsing Heap-based Buffer Overflow Remote Code Execution Vulnerability Dec 31, 2025
High CVE-2025-15278 FontForge GUtils XBM File Parsing Integer Overflow Remote Code Execution Vulnerability Dec 31, 2025
High CVE-2025-15279 FontForge GUtils BMP File Parsing Heap-based Buffer Overflow Remote Code Execution Vulnerability Dec 31, 2025
High CVE-2025-15280 FontForge SFD File Parsing Use-After-Free Remote Code Execution Vulnerability Dec 31, 2025
High CVE-2025-15271 FontForge SFD File Parsing Improper Validation of Array Index Remote Code Execution Vulnerability Dec 31, 2025
High CVE-2025-15272 FontForge SFD File Parsing Heap-based Buffer Overflow Remote Code Execution Vulnerability Dec 31, 2025

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 fixed version, patch or mitigation documented.
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-2025-15276 is "FontForge SFD File Parsing Deserialization of Untrusted Data Remote Code Execution Vulnerability", rated High. It affects Fontforge (Fontforge); 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 0.35% 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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