What is the CVSS score of CVE-2023-45139?

CVE-2023-45139 has a CVSS 3.1 base score of 7.5 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N. EPSS exploitation probability: 0.2%.

Which versions of Python are affected by CVE-2023-45139?

Organizations using fontTools face notable risk from CVE-2023-45139, a XML external entity vulnerability rated CVSS 7.5. Exploitation could compromise the security of affected deployments.. A patch is available.

Is there a public PoC exploit available for CVE-2023-45139?

Yes, a public proof-of-concept exploit is available for CVE-2023-45139. Prioritise patching immediately. EPSS: 0.2%.

How to fix or mitigate CVE-2023-45139?

Within 30 days: Identify all affected systems and apply vendor patches as part of regular patch cycle. Vendor patch is available.

Python CVE-2023-45139

HIGH

Improper Restriction of XML External Entity Reference (CWE-611)

2024-01-10 security-advisories@github.com

Python XXE Fonttools

7.5

CVSS 3.1 · GitHub Advisory

Severity by source

GitHub Advisory PRIMARY

7.5 HIGH

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

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

None

Lifecycle Timeline

Analysis Generated

Mar 28, 2026 - 19:34 vuln.today

Patch released

Mar 28, 2026 - 19:34 nvd

Patch available

PoC Detected

Nov 21, 2024 - 08:26 vuln.today

Public exploit code

CVE Published

Jan 10, 2024 - 16:15 nvd

HIGH 7.5

Blast Radius

ecosystem impact

† from your stack dependencies † transitive graph · vuln.today resolves 4-path depth

4 pypi packages depend on fonttools (4 direct, 0 indirect)

Ecosystem-wide dependent count for version 4.28.2.

DescriptionGitHub Advisory

fontTools is a library for manipulating fonts, written in Python. The subsetting module has a XML External Entity Injection (XXE) vulnerability which allows an attacker to resolve arbitrary entities when a candidate font (OT-SVG fonts), which contains a SVG table, is parsed. This allows attackers to include arbitrary files from the filesystem fontTools is running on or make web requests from the host system. This vulnerability has been patched in version 4.43.0.

AnalysisAI

fontTools is a library for manipulating fonts, written in Python. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.

Technical ContextAI

This vulnerability is classified as XML External Entity (XXE) (CWE-611), which allows attackers to read arbitrary files or perform SSRF through XML processing. fontTools is a library for manipulating fonts, written in Python. The subsetting module has a XML External Entity Injection (XXE) vulnerability which allows an attacker to resolve arbitrary entities when a candidate font (OT-SVG fonts), which contains a SVG table, is parsed. This allows attackers to include arbitrary files from the filesystem fontTools is running on or make web requests from the host system. This vulnerability has been patched in version 4.43.0. Affected products include: Fonttools. Version information: version 4.43.0..

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Disable external entity processing in XML parsers, use JSON instead of XML where possible.