DEBIAN-CVE-2026-59679
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.
DEBIAN-CVE-2026-59679
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: osv:DEBIAN-CVE-2026-59679
libxfont
Source reference: /affected/0/package/name
- Affected versions
- 1:2.0.6-1
Source reference:
/affected/0/versions1:2.0.6-1+deb12u1Source reference:
/affected/0/versions1:2.0.6-1+hurd.1Source reference:
/affected/0/versions1:2.0.6-2Source reference:
/affected/0/versions1:2.0.8-1Source reference:
/affected/0/versions1:2.0.9-1Source reference:
/affected/0/versions - Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
libxfont
Source reference: /affected/1/package/name
- Affected versions
- 1:2.0.6-1
Source reference:
/affected/1/versions1:2.0.6-1+deb13u1Source reference:
/affected/1/versions1:2.0.6-1+hurd.1Source reference:
/affected/1/versions1:2.0.6-2Source reference:
/affected/1/versions1:2.0.8-1Source reference:
/affected/1/versions1:2.0.9-1Source reference:
/affected/1/versions - Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
libxfont
Source reference: /affected/2/package/name
- Affected versions
- 1:2.0.6-1
Source reference:
/affected/2/versions1:2.0.6-1+hurd.1Source reference:
/affected/2/versions1:2.0.6-2Source reference:
/affected/2/versions1:2.0.8-1Source reference:
/affected/2/versions - Fixed versions
- 1:2.0.9-1
Source reference:
/affected/2/ranges - Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "libxfont",
"purl": "pkg:deb/debian/libxfont?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"versions": [
"1:2.0.6-1",
"1:2.0.6-1+deb12u1",
"1:2.0.6-1+hurd.1",
"1:2.0.6-2",
"1:2.0.8-1",
"1:2.0.9-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-59679.json"
},
"ecosystem_specific": {
"urgency": "unimportant"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "libxfont",
"purl": "pkg:deb/debian/libxfont?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
"1:2.0.6-1",
"1:2.0.6-1+deb13u1",
"1:2.0.6-1+hurd.1",
"1:2.0.6-2",
"1:2.0.8-1",
"1:2.0.9-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-59679.json"
},
"ecosystem_specific": {
"urgency": "unimportant"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1:2.0.9-1"
}
]
}
],
"package": {
"name": "libxfont",
"purl": "pkg:deb/debian/libxfont?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"versions": [
"1:2.0.6-1",
"1:2.0.6-1+hurd.1",
"1:2.0.6-2",
"1:2.0.8-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-59679.json"
},
"ecosystem_specific": {
"urgency": "unimportant"
}
}
]Publisher severity
No explicit severity was provided.
- Event
- #58031 · Revision 1
- Added to Heist Feed
- Publisher date