CVE-2026-34085
fontconfig before 2.17.1 has an off-by-one error in allocation during sfnt capability handling,...
fontconfig before 2.17.1 has an off-by-one error in allocation during sfnt capability handling, leading to a one-byte out-of-bounds write, and potentially a crash or code execution. This is in FcFontCapabilities in fcfreetype.c.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- Low
- Integrity
- Low
- Availability
- Low
Exploit likelihood
What each source reports
CVE List Score used
fontconfig before 2.17.1 has an off-by-one error in allocation during sfnt capability handling, leading to a one-byte out-of-bounds write, and potentially a crash or code execution. This is in FcFontCapabilities in fcfreetype.c.
- Record
CVE-2026-34085- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L - Weakness
- CWE-193
- Updated
- 2026-11-02
EUVDEUVD-2026-15934
fontconfig before 2.17.1 has an off-by-one error in allocation during sfnt capability handling, leading to a one-byte out-of-bounds write, and potentially a crash or code execution. This is in FcFontCapabilities in fcfreetype.c.
- Record
EUVD-2026-15934- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-jxv8-p782-98cx
fontconfig before 2.17.1 has an off-by-one error in allocation during sfnt capability handling,...
fontconfig before 2.17.1 has an off-by-one error in allocation during sfnt capability handling, leading to a one-byte out-of-bounds write, and potentially a crash or code execution. This is in FcFontCapabilities in fcfreetype.c.
- Record
GHSA-jxv8-p782-98cx- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L - Weakness
- CWE-193
- Updated
- 2026-11-02
NVD
fontconfig before 2.17.1 has an off-by-one error in allocation during sfnt capability handling, leading to a one-byte out-of-bounds write, and potentially a crash or code execution. This is in FcFontCapabilities in fcfreetype.c.
- Record
CVE-2026-34085- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L - CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-193
- Updated
- 2026-11-02
OSVBELL-CVE-2026-34085
CVE-2026-34085 does not affect BellSoft software
- Record
BELL-CVE-2026-34085- CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSV
fontconfig before 2.17.1 has an off-by-one error in allocation during sfnt capability handling, leading to a one-byte out-of-bounds write, and potentially a crash or code execution. This is in FcFontCapabilities in fcfreetype.c.
- Record
CVE-2026-34085- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L - Weakness
- CWE-193
- Updated
- 2026-11-02
Show 4 moreShow less
OSVDEBIAN-CVE-2026-34085
fontconfig before 2.17.1 has an off-by-one error in allocation during sfnt capability handling, leading to a one-byte out-of-bounds write, and potentially a crash or code execution. This is in FcFontCapabilities in fcfreetype.c.
- Record
DEBIAN-CVE-2026-34085- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L - Updated
- 2026-11-02
OSVJLSEC-2026-79
fontconfig before 2.17.1 has an off-by-one error in allocation during sfnt capability handling, leading to a one-byte out-of-bounds write, and potentially a crash or code execution. This is in FcFontCapabilities in fcfreetype.c.
- Record
JLSEC-2026-79- CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVRHSA-2026:13722
Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update
- Record
RHSA-2026:13722- CVSS 3.1
- 6.6 Medium
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H - Updated
- 2026-11-02
OSVUBUNTU-CVE-2026-34085
(fontconfig before 2.17.1 has an off-by-one error in allocation during ...)
- Record
UBUNTU-CVE-2026-34085- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L - CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
Fontconfig_jllJulia |
before 2.17.1+0 | 2.17.1+0 |
fontconfigRed Hat:hummingbird:1 |
before 0:2.17.1-0.1.hum1 | 0:2.17.1-0.1.hum1 |
fontconfig-develRed Hat:hummingbird:1 |
before 0:2.17.1-0.1.hum1 | 0:2.17.1-0.1.hum1 |
fontconfig-devel-docRed Hat:hummingbird:1 |
before 0:2.17.1-0.1.hum1 | 0:2.17.1-0.1.hum1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected | ||
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-34085 is a medium vulnerability (CVSS 5.9) in Fontconfig, published March 25, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.13%, the 2nd percentile. Fixed in Fontconfig_jll 2.17.1+0.
References
gitlab.freedesktop.org/fontconfig/fontconfig/-/commit/b9bec06d73340f1b5727302d13ac3df307b7febc
nvd.nist.gov/vuln/detail/CVE-2026-34085
github.com/advisories/GHSA-jxv8-p782-98cx
docs.bell-sw.com/security/cves/CVE-2026-34085
Show 10 moreShow less
security-tracker.debian.org/tracker/CVE-2026-34085
access.redhat.com/errata/RHSA-2026:13722
images.redhat.com
security.access.redhat.com/data/csaf/v2/advisories/2026/rhsa-2026_13722.json
bugzilla.redhat.com/show_bug.cgi?id=2451414
cve.org/CVERecord?id=CVE-2026-34085
ubuntu.com/security/CVE-2026-34085