CVE-2026-44950
CVE-2026-44950 — fs_read_glyphs() heap buffer overflow via cumulative glyph data overflow in libXfont2
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.
Published Updated Sources: NVD, SUSE (CNA), GitHub, GitHub Security Advisory, Red Hat (VEX), SOCRadar CTI
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.
Exploitation
Unreported
no source claims exploitation
EPSS
0%
ahead of 0% of scored CVEs
CVSS base
9
critical · 3 sources
Remediation
The vendor's own words where we have them.
Upgrade Container suse/kiosk/tigervnc-x11vnc:1.14-63.8 to a fixed release. Apply vendor patches per advisory and restrict external exposure of the affected component until patched.
Red Hat VEX · CVE-2026-44950
vendor_fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
vendor_fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
vendor_fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
First 24 hours
Ordered from the record's own fields — exposure first, because you cannot patch what you have not found.
- Identify exposed assets running affected vendor/product/version combinations.
- Prioritize based on EPSS, PoC availability, and external exposure.
- Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class.
Affected scope
Vendor, product and version as the advisories word them.
| Vendor | Product | Versions | Status |
|---|---|---|---|
| SUSE | Container suse/kiosk/tigervnc-x11vnc:1.14-63.8 | ? to < 2.0.3-150000.3.6.1 | Vulnerable |
| SUSE | Container suse/kiosk/xorg:21.1-83.7 | ? to < 2.0.3-150000.3.6.1 | Vulnerable |
| SUSE | Image SLES15-SP6-SAP | ? to < 2.0.3-150000.3.6.1 | Vulnerable |
| SUSE | Image SLES15-SP6-SAP-Azure | ? to < 2.0.3-150000.3.6.1 | Vulnerable |
| SUSE | Image SLES15-SP6-SAP-Azure-3P | ? to < 2.0.3-150000.3.6.1 | Vulnerable |
| SUSE | Image SLES15-SP6-SAP-BYOS | ? to < 2.0.3-150000.3.6.1 | Vulnerable |
| SUSE | Image SLES15-SP6-SAP-BYOS-Azure | ? to < 2.0.3-150000.3.6.1 | Vulnerable |
| SUSE | Image SLES15-SP6-SAP-BYOS-EC2 | ? to < 2.0.3-150000.3.6.1 | Vulnerable |
| SUSE | Image SLES15-SP6-SAP-BYOS-GCE | ? to < 2.0.3-150000.3.6.1 | Vulnerable |
| SUSE | Image SLES15-SP6-SAP-EC2 | ? to < 2.0.3-150000.3.6.1 | Vulnerable |
| SUSE | Image SLES15-SP6-SAP-GCE | ? to < 2.0.3-150000.3.6.1 | Vulnerable |
| SUSE | Image SLES15-SP6-SAP-Hardened | ? to < 2.0.3-150000.3.6.1 | Vulnerable |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Availability
High
Confidentiality
High
Integrity
High
Scope
Changed
Attack Complexity
High
Attack Vector
Network
Privileges Req
None
User Interaction
None
Every base score collected
Sources score independently and disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Source |
|---|---|---|---|---|---|
| 9 | CVSS 3.1 | critical | 2.2 | 6 | suse.de (CNA), SUSE (CNA), GHSA |
| 9.5 | CVSS 4.0 | critical | — | — | SUSE (CNA) |
| 7.5 | CVSS 3.1 | high | — | — | Red Hat (VEX) |
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
Weakness & attack patterns
Inferred from the weakness class — not observed against this CVE.
Detection
Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.
- Search application, proxy, and WAF logs for requests touching /fc/fserve.c).
- Prioritize edge telemetry for network-reachable Container suse/kiosk/tigervnc-x11vnc:1.14-63.8, Container suse/kiosk/xorg:21.1-83.7, Image SLES15-SP6-SAP, Image SLES15-SP6-SAP-Azure, Image SLES15-SP6-SAP-Azure-3P, Image SLES15-SP6-SAP-BYOS, Image SLES15-SP6-SAP-BYOS-Azure, Image SLES15-SP6-SAP-BYOS-EC2, Image SLES15-SP6-SAP-BYOS-GCE, Image SLES15-SP6-SAP-EC2, Image SLES15-SP6-SAP-GCE, Image SLES15-SP6-SAP-Hardened, Image SLES15-SP6-SAP-Hardened-Azure, Image SLES15-SP6-SAP-Hardened-BYOS, Image SLES15-SP6-SAP-Hardened-BYOS-Azure, Image SLES15-SP6-SAP-Hardened-BYOS-EC2, Image SLES15-SP6-SAP-Hardened-BYOS-GCE, Image SLES15-SP6-SAP-Hardened-EC2, Image SLES15-SP6-SAP-Hardened-GCE, Image SLES15-SP6-SAPCAL, Image SLES15-SP6-SAPCAL-Azure, Image SLES15-SP6-SAPCAL-EC2, Image SLES15-SP6-SAPCAL-GCE, Image SLES15-SP7-SAP-Azure, Image SLES15-SP7-SAP-Azure-3P, Image SLES15-SP7-SAP-BYOS-Azure, Image SLES15-SP7-SAP-BYOS-EC2, Image SLES15-SP7-SAP-BYOS-GCE, Image SLES15-SP7-SAP-EC2, Image SLES15-SP7-SAP-GCE, Image SLES15-SP7-SAP-GCE-3P, Image SLES15-SP7-SAP-Hardened-Azure, Image SLES15-SP7-SAP-Hardened-BYOS-Azure, Image SLES15-SP7-SAP-Hardened-BYOS-EC2, Image SLES15-SP7-SAP-Hardened-BYOS-GCE, Image SLES15-SP7-SAP-Hardened-GCE, Image SLES15-SP7-SAPCAL-Azure, Image SLES15-SP7-SAPCAL-EC2, Image SLES15-SP7-SAPCAL-GCE, Image SLES-SAP-Azure, Image SLES-SAP-Azure-3P, Image SLES-SAP-BYOS-Azure, Image SLES-SAP-BYOS-EC2, Image SLES-SAP-BYOS-GCE, Image SLES-SAP-GCE, Image SLES-SAP-GCE-3P, Image SLES-SAPCAL-GCE, Image SLES12-SP5-Azure-SAP-BYOS, Image SLES12-SP5-Azure-SAP-On-Demand, Image SLES12-SP5-EC2-SAP-BYOS, Image SLES12-SP5-EC2-SAP-On-Demand, Image SLES12-SP5-GCE-SAP-BYOS, Image SLES12-SP5-GCE-SAP-On-Demand, SUSE Liberty Linux 10, SUSE Liberty Linux 8, SUSE Liberty Linux 9, SUSE Linux Enterprise Desktop 15 SP7, SUSE Linux Enterprise Module for Basesystem 15 SP7, SUSE Linux Enterprise Server 15 SP7, SUSE Linux Enterprise Server for SAP Applications 15 SP7, SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS, SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS, SUSE Linux Enterprise High Performance Computing 15 SP5-ESPOS, SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS, SUSE Linux Enterprise Server 12 SP5-LTSS, SUSE Linux Enterprise Server 15 SP4-LTSS, SUSE Linux Enterprise Server 15 SP5-LTSS, SUSE Linux Enterprise Server 15 SP6-LTSS, SUSE Linux Enterprise Server 16.0, SUSE Linux Enterprise Server for SAP applications 16.0, SUSE Linux Enterprise Server LTSS Extended Security 12 SP5, SUSE Linux Enterprise Server for SAP Applications 15 SP4, SUSE Linux Enterprise Server for SAP Applications 15 SP5, SUSE Linux Enterprise Server for SAP Applications 15 SP6, SUSE Manager Proxy LTS 4.3, SUSE Manager Retail Branch Server LTS 4.3, SUSE Manager Server LTS 4.3, openSUSE Leap 16.0, openSUSE Tumbleweed, libXfont.
Timeline
What happened to this CVE, newest first — with the readings a source repeats on a schedule counted underneath rather than listed.
- 2026
Added · CVSS 3.1 9.0 (AV:N)
Sep 10, 2026 · NVD
Initial · CVE published
Sep 10, 2026 · NVD
Added · GHSA-72vv-3gwg-8289 published (critical)
Sep 10, 2026 · GitHub Security Advisory
CVE published by MITRE.
Sep 10, 2026 · SOCRadar CTI
References
11 on the record
- bugzilla.suse.com/show_bug.cgi?id=CVE-2026-44950
Vendor Advisory
- nvd.nist.gov/vuln/detail/CVE-2026-44950
NVD
- github.com/advisories/GHSA-72vv-3gwg-8289
Exploit, Third Party Advisory
- access.redhat.com/errata/RHSA-2026:62231
Vendor Advisory
- access.redhat.com/errata/RHSA-2026:62123
Vendor Advisory
- access.redhat.com/errata/RHSA-2026:55448
Vendor Advisory
- access.redhat.com/errata/RHSA-2026:55446
Vendor Advisory
- access.redhat.com/errata/RHSA-2026:61995
Vendor Advisory
Coverage
1 story from the feeds we poll
Elsewhere on this site
- SUSEevery CVE for this vendor
- libXfontevery CVE for this vendor
- Memory Corruptionsame class
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record1
What should defenders know first?
CVE-2026-44950 is fs_read_glyphs() heap buffer overflow via cumulative glyph data overflow in libXfont2, a critical vulnerability affecting Container suse/kiosk/tigervnc-x11vnc:1.14-63.8, Container suse/kiosk/xorg:21.1-83.7, Image SLES15-SP6-SAP, Image SLES15-SP6-SAP-Azure, Image SLES15-SP6-SAP-Azure-3P, Image SLES15-SP6-SAP-BYOS, Image SLES15-SP6-SAP-BYOS-Azure, Image SLES15-SP6-SAP-BYOS-EC2, Image SLES15-SP6-SAP-BYOS-GCE, Image SLES15-SP6-SAP-EC2, Image SLES15-SP6-SAP-GCE, Image SLES15-SP6-SAP-Hardened, Image SLES15-SP6-SAP-Hardened-Azure, Image SLES15-SP6-SAP-Hardened-BYOS, Image SLES15-SP6-SAP-Hardened-BYOS-Azure, Image SLES15-SP6-SAP-Hardened-BYOS-EC2, Image SLES15-SP6-SAP-Hardened-BYOS-GCE, Image SLES15-SP6-SAP-Hardened-EC2, Image SLES15-SP6-SAP-Hardened-GCE, Image SLES15-SP6-SAPCAL, Image SLES15-SP6-SAPCAL-Azure, Image SLES15-SP6-SAPCAL-EC2, Image SLES15-SP6-SAPCAL-GCE, Image SLES15-SP7-SAP-Azure, Image SLES15-SP7-SAP-Azure-3P, Image SLES15-SP7-SAP-BYOS-Azure, Image SLES15-SP7-SAP-BYOS-EC2, Image SLES15-SP7-SAP-BYOS-GCE, Image SLES15-SP7-SAP-EC2, Image SLES15-SP7-SAP-GCE, Image SLES15-SP7-SAP-GCE-3P, Image SLES15-SP7-SAP-Hardened-Azure, Image SLES15-SP7-SAP-Hardened-BYOS-Azure, Image SLES15-SP7-SAP-Hardened-BYOS-EC2, Image SLES15-SP7-SAP-Hardened-BYOS-GCE, Image SLES15-SP7-SAP-Hardened-GCE, Image SLES15-SP7-SAPCAL-Azure, Image SLES15-SP7-SAPCAL-EC2, Image SLES15-SP7-SAPCAL-GCE, Image SLES-SAP-Azure, Image SLES-SAP-Azure-3P, Image SLES-SAP-BYOS-Azure, Image SLES-SAP-BYOS-EC2, Image SLES-SAP-BYOS-GCE, Image SLES-SAP-GCE, Image SLES-SAP-GCE-3P, Image SLES-SAPCAL-GCE, Image SLES12-SP5-Azure-SAP-BYOS, Image SLES12-SP5-Azure-SAP-On-Demand, Image SLES12-SP5-EC2-SAP-BYOS, Image SLES12-SP5-EC2-SAP-On-Demand, Image SLES12-SP5-GCE-SAP-BYOS, Image SLES12-SP5-GCE-SAP-On-Demand, SUSE Liberty Linux 10, SUSE Liberty Linux 8, SUSE Liberty Linux 9, SUSE Linux Enterprise Desktop 15 SP7, SUSE Linux Enterprise Module for Basesystem 15 SP7, SUSE Linux Enterprise Server 15 SP7, SUSE Linux Enterprise Server for SAP Applications 15 SP7, SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS, SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS, SUSE Linux Enterprise High Performance Computing 15 SP5-ESPOS, SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS, SUSE Linux Enterprise Server 12 SP5-LTSS, SUSE Linux Enterprise Server 15 SP4-LTSS, SUSE Linux Enterprise Server 15 SP5-LTSS, SUSE Linux Enterprise Server 15 SP6-LTSS, SUSE Linux Enterprise Server 16.0, SUSE Linux Enterprise Server for SAP applications 16.0, SUSE Linux Enterprise Server LTSS Extended Security 12 SP5, SUSE Linux Enterprise Server for SAP Applications 15 SP4, SUSE Linux Enterprise Server for SAP Applications 15 SP5, SUSE Linux Enterprise Server for SAP Applications 15 SP6, SUSE Manager Proxy LTS 4.3, SUSE Manager Retail Branch Server LTS 4.3, SUSE Manager Server LTS 4.3, openSUSE Leap 16.0, openSUSE Tumbleweed, libXfont from SUSE, libXfont. The current evidence does not list it in CISA KEV, and the exploit status is: Active exploitation is not confirmed from current sources for CVE-2026-44950. Public exploit evidence is: A public PoC is not confirmed from current sources for CVE-2026-44950. The affected-version evidence is listed in the key facts and affected products tables. Defenders should first verify whether exposed or business-critical assets run those versions, then apply vendor patches or mitigations, restrict reachable attack surface, and preserve logs for detection review. CVSS 9 describes technical severity, while EPSS 0% helps estimate near-term exploit likelihood; neither replaces asset context. Unknown fields should remain explicit in tickets, and threat actor, IOC, victimology, or payload claims should not be added unless a cited source supports them. Monitor CISA KEV, vendor advisories, NVD changes, public PoC repositories, and internal telemetry for update triggers.