GUIX binary resource loader: unvalidated glyph range causes an integer underflow and a heap out-of-bounds write when loading an untrusted font or theme

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-91189
StatePUBLISHED
Assignereclipse
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-20 15:17:36 UTC
Updated2026-10-20 19:48:50 UTC
DescriptionThe GUIX binary resource loader never checks that a font page's glyph range is well formed. `gx_page_header_first_glyph` and `gx_page_header_last_glyph` are read verbatim from the file and only the upper bound of `last_glyph` is validated, so a page declaring `first_glyph > last_glyph` makes `last - first + 1` underflow to a very large unsigned count. That count is multiplied by a glyph record size to reserve the load buffer, and the multiply is unchecked, so it wraps to a small value and the loader allocates a buffer far smaller than the data it is about to write. The load pass then recomputes the count in a narrower type and writes attacker-controlled glyph records into the undersized buffer.

Risk And Classification

Primary CVSS: v4.0 7.1 HIGH from [email protected]

CVSS:4.0/AV:L/AC:H/AT:N/PR:N/UI:A/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:X

Problem Types: CWE-190 | CWE-680 | CWE-787 | CWE-190 CWE-190 Integer Overflow or Wraparound | CWE-680 CWE-680 Integer Overflow to Buffer Overflow | CWE-787 CWE-787 Out-of-bounds Write

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary7.1HIGHCVSS:4.0/AV:L/AC:H/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/C...
4.0CNACVSS7.1HIGHCVSS:4.0/AV:L/AC:H/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS v4.0 Breakdown

Attack Vector
Local
Attack Complexity
High
Attack Requirements
None
Privileges Required
None
User Interaction
Active
Confidentiality
High
Integrity
High
Availability
High
Sub Conf.
None
Sub Integrity
None
Sub Availability
None

CVSS:4.0/AV:L/AC:H/AT:N/PR:N/UI:A/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:X

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Eclipse Foundation Eclipse ThreadX - GUIX affected 6.5.1.202602a semver Not specified
CNA Eclipse Foundation Eclipse ThreadX - GUIX unaffected 6.5.2.202603 Not specified

References

ReferenceSourceLinkTags
github.com/eclipse-threadx/guix/security/advisories/GHSA-hgcj-22cg-4hfv [email protected] github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: adawn0106 (en)

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