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CVE-2026-59679

fs_read_glyphs() heap OOB read/write via encoding array index mismatch in libXfont2

CVSS score

9.0

EPSS probability

%0.3

Risk score

0.0

Published

1 mo ago

OverviewPublic Exploits (0)NewsroomVulnerability Timeline
Official patch verified

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Vulnerability description

DayBreach CVE AI Research

CVE-2026-59679 has vendor, distribution, patch and security-source records on file. We can compare them and prepare an explanation linked to the evidence.

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: Affected Products and Software

Affected Products

The following products are affected by CVE-2026-59679 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.

IDVENDORPRODUCTACTION
1suseContainer suse/kiosk/tigervnc-x11vnc:1.14-63.8 View
2suseContainer suse/kiosk/xorg:21.1-83.7 View
3suseImage SLES15-SP6-SAP View
4suseImage SLES15-SP6-SAP-Azure View
5suseImage SLES15-SP6-SAP-Azure-3P View
6suseImage SLES15-SP6-SAP-BYOS View
7suseImage SLES15-SP6-SAP-BYOS-Azure View
8suseImage SLES15-SP6-SAP-BYOS-EC2 View
9suseImage SLES15-SP6-SAP-BYOS-GCE View
10suseImage SLES15-SP6-SAP-EC2 View
11suseImage SLES15-SP6-SAP-GCE View
12suseImage SLES15-SP6-SAP-Hardened View
13suseImage SLES15-SP6-SAP-Hardened-Azure View
14suseImage SLES15-SP6-SAP-Hardened-BYOS View
15suseImage SLES15-SP6-SAP-Hardened-BYOS-Azure View
16suseImage SLES15-SP6-SAP-Hardened-BYOS-EC2 View
17suseImage SLES15-SP6-SAP-Hardened-BYOS-GCE View
18suseImage SLES15-SP6-SAP-Hardened-EC2 View
19suseImage SLES15-SP6-SAP-Hardened-GCE View
20suseImage SLES15-SP6-SAPCAL View
21suseImage SLES15-SP6-SAPCAL-Azure View
22suseImage SLES15-SP6-SAPCAL-EC2 View
23suseImage SLES15-SP6-SAPCAL-GCE View
24suseImage SLES15-SP7-SAP-Azure View
25suseImage SLES15-SP7-SAP-Azure-3P View
26suseImage SLES15-SP7-SAP-BYOS-Azure View
27suseImage SLES15-SP7-SAP-BYOS-EC2 View
28suseImage SLES15-SP7-SAP-BYOS-GCE View
29suseImage SLES15-SP7-SAP-EC2 View
30suseImage SLES15-SP7-SAP-GCE View
31suseImage SLES15-SP7-SAP-GCE-3P View
32suseImage SLES15-SP7-SAP-Hardened-Azure View
33suseImage SLES15-SP7-SAP-Hardened-BYOS-Azure View
34suseImage SLES15-SP7-SAP-Hardened-BYOS-EC2 View
35suseImage SLES15-SP7-SAP-Hardened-BYOS-GCE View
36suseImage SLES15-SP7-SAP-Hardened-GCE View
37suseImage SLES15-SP7-SAPCAL-Azure View
38suseImage SLES15-SP7-SAPCAL-EC2 View
39suseImage SLES15-SP7-SAPCAL-GCE View
40suseImage SLES-SAP-Azure View
41suseImage SLES-SAP-Azure-3P View
42suseImage SLES-SAP-BYOS-Azure View
43suseImage SLES-SAP-BYOS-EC2 View
44suseImage SLES-SAP-BYOS-GCE View
45suseImage SLES-SAP-GCE View
46suseImage SLES-SAP-GCE-3P View
47suseImage SLES-SAPCAL-GCE View
48suseImage SLES12-SP5-Azure-SAP-BYOS View
49suseImage SLES12-SP5-Azure-SAP-On-Demand View
50suseImage SLES12-SP5-EC2-SAP-BYOS View
51suseImage SLES12-SP5-EC2-SAP-On-Demand View
52suseImage SLES12-SP5-GCE-SAP-BYOS View
53suseImage SLES12-SP5-GCE-SAP-On-Demand View
54suseSUSE Liberty Linux 10 View
55suseSUSE Liberty Linux 8 View
56suseSUSE Liberty Linux 9 View
57suseSUSE Linux Enterprise Desktop 15 SP7 View
58suseSUSE Linux Enterprise Module for Basesystem 15 SP7 View
59suseSUSE Linux Enterprise Server 15 SP7 View
60suseSUSE Linux Enterprise Server for SAP Applications 15 SP7 View
61suseSUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS View
62suseSUSE Linux Enterprise High Performance Computing 15 SP4-LTSS View
63suseSUSE Linux Enterprise High Performance Computing 15 SP5-ESPOS View
64suseSUSE Linux Enterprise High Performance Computing 15 SP5-LTSS View
65suseSUSE Linux Enterprise Server 12 SP5-LTSS View
66suseSUSE Linux Enterprise Server 15 SP4-LTSS View
67suseSUSE Linux Enterprise Server 15 SP5-LTSS View
68suseSUSE Linux Enterprise Server 15 SP6-LTSS View
69suseSUSE Linux Enterprise Server 16.0 View
70suseSUSE Linux Enterprise Server for SAP applications 16.0 View
71suseSUSE Linux Enterprise Server LTSS Extended Security 12 SP5 View
72suseSUSE Linux Enterprise Server for SAP Applications 15 SP4 View
73suseSUSE Linux Enterprise Server for SAP Applications 15 SP5 View
74suseSUSE Linux Enterprise Server for SAP Applications 15 SP6 View
75suseSUSE Manager Proxy LTS 4.3 View
76suseSUSE Manager Retail Branch Server LTS 4.3 View
77suseSUSE Manager Server LTS 4.3 View
78suseopenSUSE Leap 16.0 View
79suseopenSUSE Tumbleweed View
80libXfont2libXfont2 View
Total affected vendors: 2|Products: 80

RED HAT CSAF/VEX: Product Impact Check

Red Hat has not yet published a CSAF/VEX impact record for this CVE. This does not mean “not affected”.

SCORING: CVSS from Multiple Sources

CVSS Scores

The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.

SCOREVERSIONSEVERITYVECTORSOURCE
9.2CVSS V4_0CRITICALCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:NCVE CNA
9.2CVSS V40CRITICALCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:XNVD
9.0CVSS V3_1CRITICALCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:HCVE CNA
9.0CVSS V31CRITICALCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:HNVD
9.0CVSS 3.x—CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:HMicrosoft MSRC

Patch and Remediation Guide

Solution & Remediation Advisory

Patch verified

1 doğrulanmış yama veya düzeltilmiş sürüm kanıtı bulundu.

reference

Yama veya çözüm referansı

Open source
Confirm the affected product and version against the source evidence above.
Restrict access to internet-facing services and apply network segmentation.
Apply the official update named in the evidence only to the matching product and version.
Monitor server logs and network endpoints for signs of anomalous execution.

Public exploit and active exploitation status

Verified exploit intelligence

No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.

Weakness Classification and Attack Patterns (CWE & CAPEC)

CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-59679 is associated with the following CWEs:

CWE-787: Out-of-bounds Write

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-59679 weaknesses.

CAPEC-66: SQL InjectionCAPEC-126: Path TraversalCAPEC-28: OS Command Injection

Attack Vector and Accessibility

ExposureAğ üzerinden
PermissionsGerekmiyor
UserGerekmiyor

Official Sources and Advisories

https://bugzilla.suse.com/show_bug.cgi?id=CVE-2026-59679vendor-advisoryhttps://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgradepatch

CVSS Vector Radar Chart

9.0 / 10
Attack VectorNetworkComplexityHighPrivilegesNoneUser Interact.NoneConfidentialityHighIntegrityNoneAvailabilityHigh

Vulnerability Scoring Details

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
Attack VectorNetwork
Attack ComplexityHigh
Privileges RequiredNone required
User InteractionNone required
Confidentiality (Gizlilik)High
Integrity (Bütünlük)None
Availability (Erişilebilirlik)High

Yama doğrulandı

1 doğrulanmış yama veya düzeltilmiş sürüm kanıtı bulundu.

Follow the vendor

S
suse logo
suse
L
libXfont2 logo
libXfont2

Weakness Type (CWE & CAPEC)

CWE-787

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