CVE-2026-59679Critical· 9.0▾ Midnight

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…

▾ Midnight zone — Critical, or high with PoC / in-the-wild

Depth score50/ 100 · Moderate

impact 49.5 · likelihood 0.1 · exploitation 0

⚡ Agent-ready:Raw markdown ↗JSON ↗

Proof of concept

Need a working PoC? Pro members can cast a request and our team develops one — it lands right here.

…

Published

Sep 10, 2026

Updated

Sep 10, 2026

CVSS

9.0

Vendor

SUSE

Product

libXfont2-2

CWE

CWE-787

Depth score

50 · Moderate

EPSS

0.41% · p35

Platforms

—

Source

NVD

Vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

CISA SSVC

decided 2026-09-10

Exploitation: none
Automatable: no
Technical impact: total

Stakeholder-Specific Vulnerability Categorization from CISA's ADP record at CVE.org: whether exploitation is observed, whether an attack can be automated, and how much of the system is at stake.

EPSS history

Exploit-prediction probability, daily snapshots since Sep 11.

0.4% → 0.4%

Timeline

Disclosure to exploitation, from the record and what we observed since indexing it.

2 events · 1 day

Sep 10, 2026Published
Disclosed via NVD
Sep 11, 2026EPSS first tracked
0.4%

SUSE CWE-787 #nvd #cve.org

Affected

libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.7-160000.5.1
libXfont2-2 >= ? < 2.0.7-160000.5.1
libXfont2-2 >= ? < 2.0.7-160000.5.1
libXfont2-2 >= ? < 2.0.7-160000.5.1
libXfont2-2 >= ? < 2.0.7-160000.5.1
libXfont2-2 >= ? < 2.0.7-160000.5.1
libXfont2-2 >= ? < 2.0.7-160000.5.1
libXfont2-2 >= ? < 2.0.7-160000.5.1
libXfont2-2 >= ? < 2.0.3-3.6.1
libXfont2-2 >= ? < 2.0.3-3.6.1
libXfont2-2 >= ? < 2.0.3-3.6.1

Full technical detail▾

Overview

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.

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

References

[email protected] — https://bugzilla.suse.com/show_bug.cgi?id=CVE-2026-59679

Related vulnerabilities

Connected by shared product, vendor, weakness, or advisory.

#nvd#cve.org

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CVE-2026-59679Critical· 9.0▾ Midnight

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…

▾ Midnight zone — Critical, or high with PoC / in-the-wild

Depth score50/ 100 · Moderate

impact 49.5 · likelihood 0.1 · exploitation 0

⚡ Agent-ready:Raw markdown ↗JSON ↗

Proof of concept

Need a working PoC? Pro members can cast a request and our team develops one — it lands right here.

…

Published

Sep 10, 2026

Updated

Sep 10, 2026

CVSS

9.0

Vendor

SUSE

Product

libXfont2-2

CWE

CWE-787

Depth score

50 · Moderate

EPSS

0.41% · p35

Platforms

—

Source

NVD

Vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

CISA SSVC

decided 2026-09-10

Exploitation: none
Automatable: no
Technical impact: total

Stakeholder-Specific Vulnerability Categorization from CISA's ADP record at CVE.org: whether exploitation is observed, whether an attack can be automated, and how much of the system is at stake.

EPSS history

Exploit-prediction probability, daily snapshots since Sep 11.

0.4% → 0.4%

Timeline

Disclosure to exploitation, from the record and what we observed since indexing it.

2 events · 1 day

Sep 10, 2026Published
Disclosed via NVD
Sep 11, 2026EPSS first tracked
0.4%

SUSE CWE-787 #nvd #cve.org

Affected

libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.3-150000.3.6.1
libXfont2-2 >= ? < 2.0.7-160000.5.1
libXfont2-2 >= ? < 2.0.7-160000.5.1
libXfont2-2 >= ? < 2.0.7-160000.5.1
libXfont2-2 >= ? < 2.0.7-160000.5.1
libXfont2-2 >= ? < 2.0.7-160000.5.1
libXfont2-2 >= ? < 2.0.7-160000.5.1
libXfont2-2 >= ? < 2.0.7-160000.5.1
libXfont2-2 >= ? < 2.0.7-160000.5.1
libXfont2-2 >= ? < 2.0.3-3.6.1
libXfont2-2 >= ? < 2.0.3-3.6.1
libXfont2-2 >= ? < 2.0.3-3.6.1

Full technical detail▾

Overview

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

References

[email protected] — https://bugzilla.suse.com/show_bug.cgi?id=CVE-2026-59679

Related vulnerabilities

Connected by shared product, vendor, weakness, or advisory.

#nvd#cve.org