CVE-2026-59679: libXfont2 · Vulnerability
Affects libXfont2 libXfont2Source CVE Database V5
Not known to be exploited · CVSS 9.0 Critical.
Data as of 10/25/2026, 16:58:56 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 17% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 10 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wild: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| SUSEContainer suse/kiosk/tigervnc-x11vnc:1.14-63.8 | Affected– | Fixed in
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| SUSEContainer suse/kiosk/xorg:21.1-83.7 | Affected– | Fixed in
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| SUSEImage SLES15-SP6-SAP | Affected– | Fixed in
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| SUSEImage SLES15-SP6-SAP-Azure | Affected– | Fixed in
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| SUSEImage SLES15-SP6-SAP-Azure-3P | Affected– | Fixed in
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| SUSEImage SLES15-SP6-SAP-BYOS | Affected– | Fixed in
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| SUSEImage SLES15-SP6-SAP-BYOS-Azure | Affected– | Fixed in
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| SUSEImage SLES15-SP6-SAP-BYOS-EC2 | Affected– | Fixed in
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| SUSEImage SLES15-SP6-SAP-BYOS-GCE | Affected– | Fixed in
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| SUSEImage SLES15-SP6-SAP-EC2 | Affected– | Fixed in
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| SUSEImage SLES15-SP6-SAP-GCE | Affected– | Fixed in
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| SUSEImage SLES15-SP6-SAP-Hardened | Affected– | Fixed in
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| SUSEImage SLES15-SP6-SAP-Hardened-Azure | Affected– | Fixed in
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| SUSEImage SLES15-SP6-SAP-Hardened-BYOS | Affected– | Fixed in
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| SUSEImage SLES15-SP6-SAP-Hardened-BYOS-Azure | Affected– | Fixed in
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| SUSEImage SLES15-SP6-SAP-Hardened-BYOS-EC2 | Affected– | Fixed in
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| SUSEImage SLES15-SP6-SAP-Hardened-BYOS-GCE | Affected– | Fixed in
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| SUSEImage SLES15-SP6-SAP-Hardened-EC2 | Affected– | Fixed in
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| SUSEImage SLES15-SP6-SAP-Hardened-GCE | Affected– | Fixed in
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| SUSEImage SLES15-SP6-SAPCAL | Affected– | Fixed in
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| SUSEImage SLES15-SP6-SAPCAL-Azure | Affected– | Fixed in
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| SUSEImage SLES15-SP6-SAPCAL-EC2 | Affected– | Fixed in
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| SUSEImage SLES15-SP6-SAPCAL-GCE | Affected– | Fixed in
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| SUSEImage SLES15-SP7-SAP-Azure | Affected– | Fixed in
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| SUSEImage SLES15-SP7-SAP-Azure-3P | Affected– | Fixed in
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| SUSEImage SLES15-SP7-SAP-BYOS-Azure | Affected– | Fixed in
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| SUSEImage SLES15-SP7-SAP-BYOS-EC2 | Affected– | Fixed in
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| SUSEImage SLES15-SP7-SAP-BYOS-GCE | Affected– | Fixed in
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| SUSEImage SLES15-SP7-SAP-EC2 | Affected– | Fixed in
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| SUSEImage SLES15-SP7-SAP-GCE | Affected– | Fixed in
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| SUSEImage SLES15-SP7-SAP-GCE-3P | Affected– | Fixed in
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| SUSEImage SLES15-SP7-SAP-Hardened-Azure | Affected– | Fixed in
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| SUSEImage SLES15-SP7-SAP-Hardened-BYOS-Azure | Affected– | Fixed in
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| SUSEImage SLES15-SP7-SAP-Hardened-BYOS-EC2 | Affected– | Fixed in
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| SUSEImage SLES15-SP7-SAP-Hardened-BYOS-GCE | Affected– | Fixed in
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| SUSEImage SLES15-SP7-SAP-Hardened-GCE | Affected– | Fixed in
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| SUSEImage SLES15-SP7-SAPCAL-Azure | Affected– | Fixed in
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| SUSEImage SLES15-SP7-SAPCAL-EC2 | Affected– | Fixed in
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| SUSEImage SLES15-SP7-SAPCAL-GCE | Affected– | Fixed in
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| SUSEImage SLES-SAP-Azure | Affected– | Fixed in
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| SUSEImage SLES-SAP-Azure-3P | Affected– | Fixed in
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| SUSEImage SLES-SAP-BYOS-Azure | Affected– | Fixed in
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| SUSEImage SLES-SAP-BYOS-EC2 | Affected– | Fixed in
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| SUSEImage SLES-SAP-BYOS-GCE | Affected– | Fixed in
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| SUSEImage SLES-SAP-GCE | Affected– | Fixed in
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| SUSEImage SLES-SAP-GCE-3P | Affected– | Fixed in
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| SUSEImage SLES-SAPCAL-GCE | Affected– | Fixed in
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| SUSEImage SLES12-SP5-Azure-SAP-BYOS | Affected– | Fixed in
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| SUSEImage SLES12-SP5-Azure-SAP-On-Demand | Affected– | Fixed in
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| SUSEImage SLES12-SP5-EC2-SAP-BYOS | Affected– | Fixed in
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| SUSEImage SLES12-SP5-EC2-SAP-On-Demand | Affected– | Fixed in
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| SUSEImage SLES12-SP5-GCE-SAP-BYOS | Affected– | Fixed in
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| SUSEImage SLES12-SP5-GCE-SAP-On-Demand | Affected– | Fixed in
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| SUSESUSE Liberty Linux 10 | Affected– | Fixed in
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| SUSESUSE Liberty Linux 8 | Affected– | Fixed in
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| SUSESUSE Liberty Linux 9 | Affected– | Fixed in
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| SUSESUSE Linux Enterprise Desktop 15 SP7 | Affected– | Fixed in
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| SUSESUSE Linux Enterprise Module for Basesystem 15 SP7 | Affected– | Fixed in
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| SUSESUSE Linux Enterprise Server 15 SP7 | Affected– | Fixed in
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| SUSESUSE Linux Enterprise Server for SAP Applications 15 SP7 | Affected– | Fixed in
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| SUSESUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS | Affected– | Fixed in
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| SUSESUSE Linux Enterprise High Performance Computing 15 SP4-LTSS | Affected– | Fixed in
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| SUSESUSE Linux Enterprise High Performance Computing 15 SP5-ESPOS | Affected– | Fixed in
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| SUSESUSE Linux Enterprise High Performance Computing 15 SP5-LTSS | Affected– | Fixed in
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| SUSESUSE Linux Enterprise Server 12 SP5-LTSS | Affected– | Fixed in
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| SUSESUSE Linux Enterprise Server 15 SP4-LTSS | Affected– | Fixed in
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| SUSESUSE Linux Enterprise Server 15 SP5-LTSS | Affected– | Fixed in
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| SUSESUSE Linux Enterprise Server 15 SP6-LTSS | Affected– | Fixed in
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| SUSESUSE Linux Enterprise Server 16.0 | Affected– | Fixed in
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| SUSESUSE Linux Enterprise Server for SAP applications 16.0 | Affected– | Fixed in
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| SUSESUSE Linux Enterprise Server LTSS Extended Security 12 SP5 | Affected– | Fixed in
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| SUSESUSE Linux Enterprise Server for SAP Applications 15 SP4 | Affected– | Fixed in
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| SUSESUSE Linux Enterprise Server for SAP Applications 15 SP5 | Affected– | Fixed in
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| SUSESUSE Linux Enterprise Server for SAP Applications 15 SP6 | Affected– | Fixed in
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| SUSESUSE Manager Proxy LTS 4.3 | Affected– | Fixed in
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| SUSESUSE Manager Retail Branch Server LTS 4.3 | Affected– | Fixed in
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| SUSESUSE Manager Server LTS 4.3 | Affected– | Fixed in
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| SUSEopenSUSE Leap 16.0 | Affected– | Fixed in
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| SUSEopenSUSE Tumbleweed | Affected– | Fixed in
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| libXfont2libXfont2 | Affected– | Fixed in– |
AI-suggested
Users should monitor the vendor advisory for updates and apply any official fixes once available. Until then, avoid connecting to untrusted font servers or restrict font server access to trusted sources only.
Description
fs_read_glyphs() in the libXfont2 font-server client (src/fc/fserve.c) indexes the per-character encoding[] array using num_chars from the FS_QueryXBitmaps16 reply, but that array was allocated with a size derived from num_extents in the separate FS_QueryXExtents16 reply. The two CARD32 fields are never cross-checked. A malicious or compromised font server can send a small num_extents (e.g. 1) in the extents reply, then a large num_chars (e.g. 100000) in the bitmaps reply. This causes attacker-controlled out-of-bounds heap read and writes.
Impact
This vulnerability allows an attacker controlling or compromising the font server to cause out-of-bounds heap reads and writes in the client, potentially leading to arbitrary code execution, denial of service, or data corruption. The CVSS score of 9.0 indicates a critical severity with high impact on confidentiality, integrity, and availability without requiring privileges or user interaction.
Weaknesses
- CWE-787Out-of-bounds Write (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #5
The product writes data past the end, or before the beginning, of the intended buffer.