{"id":"CVE-2026-91189","state":"PUBLISHED","title":"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","description":"The 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.\n\n\n\nThat 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.","publishedAt":"2026-10-20T14:53:44.860Z","updatedAt":"2026-10-20T15:25:24.066Z","severity":{"score":7.1,"label":"High","version":"4.0","vector":"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","source":"eclipse"},"assigner":"eclipse","products":["Eclipse Foundation Eclipse ThreadX - GUIX"],"affected":[{"vendor":"Eclipse Foundation","product":"Eclipse ThreadX - GUIX","packageName":"GUIX","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThanOrEqual":"6.5.1.202602a","versionType":"semver"},{"version":"6.5.2.202603","status":"unaffected"}]}],"references":["https://github.com/eclipse-threadx/guix/security/advisories/GHSA-hgcj-22cg-4hfv"],"weaknesses":["CWE-190","CWE-680","CWE-787"],"ingestedAt":"2026-10-29T20:13:34.582Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/91xxx/CVE-2026-91189.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-91189","state":"PUBLISHED","datePublished":"2026-10-20T14:53:44.860Z","dateUpdated":"2026-10-20T15:25:24.066Z","assignerShortName":"eclipse","assignerOrgId":"e51fbebd-6053-4e49-959f-1b94eeb69a2c","dateReserved":"2026-09-23T13:43:04.319Z"},"containers":{"cna":{"title":"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","descriptions":[{"lang":"en","value":"The 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.\n\n\n\nThat 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."}],"affected":[{"vendor":"Eclipse Foundation","product":"Eclipse ThreadX - GUIX","packageName":"GUIX","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThanOrEqual":"6.5.1.202602a","versionType":"semver"},{"version":"6.5.2.202603","status":"unaffected"}]}],"references":[{"url":"https://github.com/eclipse-threadx/guix/security/advisories/GHSA-hgcj-22cg-4hfv"}],"metrics":[{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV4_0":{"attackVector":"LOCAL","attackComplexity":"HIGH","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"ACTIVE","vulnConfidentialityImpact":"HIGH","subConfidentialityImpact":"NONE","vulnIntegrityImpact":"HIGH","subIntegrityImpact":"NONE","vulnAvailabilityImpact":"HIGH","subAvailabilityImpact":"NONE","exploitMaturity":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED","version":"4.0","baseSeverity":"HIGH","baseScore":7.1,"vectorString":"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"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-190","lang":"en","description":"CWE-190 Integer Overflow or Wraparound","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-680","lang":"en","description":"CWE-680 Integer Overflow to Buffer Overflow","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-787","lang":"en","description":"CWE-787 Out-of-bounds Write","type":"CWE"}]}],"providerMetadata":{"shortName":"eclipse","orgId":"e51fbebd-6053-4e49-959f-1b94eeb69a2c","dateUpdated":"2026-10-20T14:53:44.860Z"},"credits":[{"lang":"en","value":"adawn0106","type":"reporter"}],"source":{"discovery":"UNKNOWN"},"x_generator":{"engine":"Vulnogram 1.0.5"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-10-20T15:24:56.279111Z","id":"CVE-2026-91189","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-20T15:25:24.066Z"}}]}}}