CVE-2026-44950
CRITICALCVSS 9/10EPSS 0.44%
Last modified
CVE-2026-44950 is a critical-severity vulnerability rated 9/10 on the CVSS scale. fs_read_glyphs() in the libXfont2 font-server client (src/fc/fserve.c) copies each glyph's bitmap into a single buffer. Existing checks validates only that the source slice (position, length) lies within the source bitmap buffer. EPSS estimates a 0.44% chance of exploitation in the next 30 days.
Description
fs_read_glyphs() in the libXfont2 font-server client (src/fc/fserve.c) copies each glyph's bitmap into a single buffer. Existing checks validates only that the source slice (position, length) lies within the source bitmap buffer. It does not check whether the running destination cursor has exceeded the allocation. A malicious font server can send overlapping source offsets -- for example 1000 glyphs each referencing {position:0, length:64} with nbytes=64. Each individual source range passes the existing validation, but the cumulative writes total 64000 bytes into a 64-byte destination buffer. This is a heap buffer overflow with attacker-controlled content.
Metrics
Weakness Enumeration
Affected Software
Source: CNA advisory (CVE.org). NVD analysis pending.
| Vendor | Product | Versions |
|---|---|---|
| SUSE | Container suse/kiosk/tigervnc-x11vnc:1.14-63.8 | >= ?, < 2.0.3-150000.3.6.1 |
| SUSE | Container suse/kiosk/xorg:21.1-83.7 | >= ?, < 2.0.3-150000.3.6.1 |
| SUSE | Image SLES15-SP6-SAP | >= ?, < 2.0.3-150000.3.6.1 |
| SUSE | Image SLES15-SP6-SAP-Azure | >= ?, < 2.0.3-150000.3.6.1 |
| SUSE | Image SLES15-SP6-SAP-Azure-3P | >= ?, < 2.0.3-150000.3.6.1 |
| SUSE | Image SLES15-SP6-SAP-BYOS | >= ?, < 2.0.3-150000.3.6.1 |
| SUSE | Image SLES15-SP6-SAP-BYOS-Azure | >= ?, < 2.0.3-150000.3.6.1 |
| SUSE | Image SLES15-SP6-SAP-BYOS-EC2 | >= ?, < 2.0.3-150000.3.6.1 |
| SUSE | Image SLES15-SP6-SAP-BYOS-GCE | >= ?, < 2.0.3-150000.3.6.1 |
| SUSE | Image SLES15-SP6-SAP-EC2 | >= ?, < 2.0.3-150000.3.6.1 |
| SUSE | Image SLES15-SP6-SAP-GCE | >= ?, < 2.0.3-150000.3.6.1 |
| SUSE | Image SLES15-SP6-SAP-Hardened | >= ?, < 2.0.3-150000.3.6.1 |
| SUSE | Image SLES15-SP6-SAP-Hardened-Azure | >= ?, < 2.0.3-150000.3.6.1 |
| SUSE | Image SLES15-SP6-SAP-Hardened-BYOS | >= ?, < 2.0.3-150000.3.6.1 |
| SUSE | Image SLES15-SP6-SAP-Hardened-BYOS-Azure | >= ?, < 2.0.3-150000.3.6.1 |
| SUSE | Image SLES15-SP6-SAP-Hardened-BYOS-EC2 | >= ?, < 2.0.3-150000.3.6.1 |
| SUSE | Image SLES15-SP6-SAP-Hardened-BYOS-GCE | >= ?, < 2.0.3-150000.3.6.1 |
| SUSE | Image SLES15-SP6-SAP-Hardened-EC2 | >= ?, < 2.0.3-150000.3.6.1 |
| SUSE | Image SLES15-SP6-SAP-Hardened-GCE | >= ?, < 2.0.3-150000.3.6.1 |
| SUSE | Image SLES15-SP6-SAPCAL | >= ?, < 2.0.3-150000.3.6.1 |
| SUSE | Image SLES15-SP6-SAPCAL-Azure | >= ?, < 2.0.3-150000.3.6.1 |
| SUSE | Image SLES15-SP6-SAPCAL-EC2 | >= ?, < 2.0.3-150000.3.6.1 |
| SUSE | Image SLES15-SP6-SAPCAL-GCE | >= ?, < 2.0.3-150000.3.6.1 |
| SUSE | Image SLES15-SP7-SAP-Azure | >= ?, < 2.0.3-150000.3.6.1 |
| SUSE | Image SLES15-SP7-SAP-Azure-3P | >= ?, < 2.0.3-150000.3.6.1 |
| SUSE | Image SLES15-SP7-SAP-BYOS-Azure | >= ?, < 2.0.3-150000.3.6.1 |
| SUSE | Image SLES15-SP7-SAP-BYOS-EC2 | >= ?, < 2.0.3-150000.3.6.1 |
| SUSE | Image SLES15-SP7-SAP-BYOS-GCE | >= ?, < 2.0.3-150000.3.6.1 |
| SUSE | Image SLES15-SP7-SAP-EC2 | >= ?, < 2.0.3-150000.3.6.1 |
| SUSE | Image SLES15-SP7-SAP-GCE | >= ?, < 2.0.3-150000.3.6.1 |
| SUSE | Image SLES15-SP7-SAP-GCE-3P | >= ?, < 2.0.3-150000.3.6.1 |
| SUSE | Image SLES15-SP7-SAP-Hardened-Azure | >= ?, < 2.0.3-150000.3.6.1 |
| SUSE | Image SLES15-SP7-SAP-Hardened-BYOS-Azure | >= ?, < 2.0.3-150000.3.6.1 |
| SUSE | Image SLES15-SP7-SAP-Hardened-BYOS-EC2 | >= ?, < 2.0.3-150000.3.6.1 |
| SUSE | Image SLES15-SP7-SAP-Hardened-BYOS-GCE | >= ?, < 2.0.3-150000.3.6.1 |
| SUSE | Image SLES15-SP7-SAP-Hardened-GCE | >= ?, < 2.0.3-150000.3.6.1 |
| SUSE | Image SLES15-SP7-SAPCAL-Azure | >= ?, < 2.0.3-150000.3.6.1 |
| SUSE | Image SLES15-SP7-SAPCAL-EC2 | >= ?, < 2.0.3-150000.3.6.1 |
| SUSE | Image SLES15-SP7-SAPCAL-GCE | >= ?, < 2.0.3-150000.3.6.1 |
| SUSE | Image SLES-SAP-Azure | >= ?, < 2.0.7-160000.5.1 |
| SUSE | Image SLES-SAP-Azure-3P | >= ?, < 2.0.7-160000.5.1 |
| SUSE | Image SLES-SAP-BYOS-Azure | >= ?, < 2.0.7-160000.5.1 |
| SUSE | Image SLES-SAP-BYOS-EC2 | >= ?, < 2.0.7-160000.5.1 |
| SUSE | Image SLES-SAP-BYOS-GCE | >= ?, < 2.0.7-160000.5.1 |
| SUSE | Image SLES-SAP-GCE | >= ?, < 2.0.7-160000.5.1 |
| SUSE | Image SLES-SAP-GCE-3P | >= ?, < 2.0.7-160000.5.1 |
| SUSE | Image SLES-SAPCAL-GCE | >= ?, < 2.0.7-160000.5.1 |
| SUSE | Image SLES12-SP5-Azure-SAP-BYOS | >= ?, < 2.0.3-3.6.1 |
| SUSE | Image SLES12-SP5-Azure-SAP-On-Demand | >= ?, < 2.0.3-3.6.1 |
| SUSE | Image SLES12-SP5-EC2-SAP-BYOS | >= ?, < 2.0.3-3.6.1 |
Showing 50 of 80 affected configurations. See the CNA advisory for the full list.
References
Timeline
- Published
- Last Modified
- Status
- Awaiting Analysis
Frequently Asked Questions
What is CVE-2026-44950?
fs_read_glyphs() in the libXfont2 font-server client (src/fc/fserve.c) copies each glyph's bitmap into a single buffer. Existing checks validates only that the source slice (position, length) lies within the source bitmap buffer. It does not check whether the running destination cursor has exceeded the allocation.
A malicious font server can send overlapping source offsets -- for example 1000 glyphs each referencing {position:0, length:64} with nbytes=64. Each individual source range passes the existing validation, but the cumulative writes total 64000 bytes into a 64-byte destination buffer. This is a heap buffer overflow with attacker-controlled content.
How severe is CVE-2026-44950?
CVE-2026-44950 has a CVSS score of 9/10 (CRITICAL severity). The EPSS model estimates a 0.44% probability of exploitation in the next 30 days.
How do I fix CVE-2026-44950?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.
How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
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