What is CVE-2026-59679?

CVE-2026-59679 is fs_read_glyphs() heap OOB read/write via encoding array index mismatch in libXfont2. The supplied enrichment data classifies it as Unclassified mapped to Not reported.

Which versions are affected?

Affected product and version evidence is listed in the product table above. Current public advisories should be checked for exact version scope before patch targeting is finalized.

Is there active exploitation?

Active exploitation is not confirmed from current sources for CVE-2026-59679. If exploitation is not confirmed from current sources, teams should document that status and continue monitoring KEV, vendor, and telemetry updates.

No. CVE-2026-59679 is not listed in CISA KEV in the supplied enrichment data. KEV status should be monitored because it can change after initial disclosure or after exploitation becomes publicly confirmed.

Is there a public exploit?

A public PoC is not confirmed from current sources for CVE-2026-59679. Public exploit or PoC availability should raise triage priority, especially for exposed or business-critical systems.

How can defenders detect it?

Start with web/proxy/WAF logs, application logs, network IDS/IPS where available. Look for vulnerability-class behavior, product errors, suspicious authentication events, exploit probes, and abnormal process activity based only on evidence that applies to the affected product.

How should teams prioritize it?

Prioritize CVE-2026-59679 using CVSS 9, EPSS 0%, KEV status, public PoC status, and asset exposure. Internet-facing, privileged, or business-critical deployments should be handled first.

Are workarounds available?

The supplied mitigation guidance says to apply vendor patches and restrict external exposure until fixed. Fixed-version evidence is listed in the mitigation section above.

Which threat actors are linked publicly?

No public threat actor linkage is confirmed from current sources. Do not attribute exploitation to a threat actor unless the source evidence explicitly supports that linkage.

What should be done in the next 24 hours?

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. Open remediation tickets with affected assets, owners, evidence status, and detection coverage so decisions are traceable.

critical

CVE-2026-59679

CVE-2026-59679 — fs_read_glyphs() heap OOB read/write via encoding array index mismatch in libXfont2

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.

Published Sep 10, 2026Updated Sep 10, 2026Sources: 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

ahead of 0% of scored CVEs

Affects

SUSE

106 products listed

CVSS base

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-2026-59679

fixed249affected0not affected0

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
9.2	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

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, libXfont2.

web/proxy/WAF logsapplication logsnetwork IDS/IPS

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-g44m-wpf7-gr7x 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-2026-59679
Vendor Advisory
nvd.nist.gov/vuln/detail/CVE-2026-59679
NVD
github.com/advisories/GHSA-g44m-wpf7-gr7x
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

2 stories from the feeds we poll

Elsewhere on this site

SUSEevery CVE for this vendor
libXfont2every CVE for this vendor
Unclassifiedsame 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-2026-59679 is fs_read_glyphs() heap OOB read/write via encoding array index mismatch 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, libXfont2 from SUSE, libXfont2. 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-2026-59679. Public exploit evidence is: A public PoC is not confirmed from current sources for CVE-2026-59679. 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.