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Fencer Vulns
high 7.5

CVE-2023-45139 json

fonttools XML External Entity Injection (XXE) Vulnerability

published 2024-01-09 2 y ago modified 2026-09-10 1 mo ago also GHSA-6673-4983-2vx5 , PYSEC-2026-1388 , EUVD-2024-0267

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.2%
EPSS 1.2% chance of exploitation in 30 days, percentile 69%
public exploits
0
none known

Summary

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.

Patch / fix

  • pypi fonttools 4.43.0
  • fonttools fonttools 4.43.0
  • fonttools Debian 12 4.38.0-1+deb12u1
  • fonttools Debian 14, Debian 13 4.46.0-1

debian advisories DEBIAN-CVE-2023-45139

  • fonttools Ubuntu Pro 22.04 LTS 4.29.1-2ubuntu0.1~esm1

ubuntu advisories UBUNTU-CVE-2023-45139

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • python-FontTools openSUSE Tumbleweed 4.62.1-1.3

opensuse advisories openSUSE-SU-2026:11991-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2023-45139 updated cvss 7.5

fonttools: XML External Entity Injection (XXE) Vulnerability

  • Red Hat Enterprise Linux 7 fonttools Red Hat Enterprise Linux 8 google-noto-emoji-fonts, google-noto-emoji-color-fonts Red Hat Enterprise Linux 9 google-noto-emoji-fonts, google-noto-emoji-color-fonts
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
18 mo ago

Exploit prediction

1.23% chance of exploitation in the next 30 days, higher than 69% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/fonttools/fonttools/security/advisories/GHSA-6673-4983-2vx5 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
OSV 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected packages

ecosystem package affected fixed in
pypi fonttools
>=4.28.2, <4.43.0
4.43.0

Affected products

  • fonttools fonttools

Classification

Weakness
  • CWE-611 Improper Restriction of XML External Entity Reference

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.