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Vulnerabilities

Vulnerability · CVE-2026-91189

The GUIX binary resource loader never checks that a font page's glyph range is well formed.

Published Oct 20, 2026 · catalog updated Oct 20, 2026 · The GUIX binary resource

Last checked Nov 7, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-91189. EPSS is 0.14%. Act only if a listed version of The GUIX binary resource is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (The GUIX binary resource).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High7.1
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.14%
Remediation
Advisory link
Affected products
See sources for product scope

The GUIX binary resource loader never checks that a font page's glyph range is well formed. and are read verbatim from the file and only the upper bound of is validated, so a page declaring makes 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.

No affected version ranges are stored yet. Use the vendor advisory before you decide this record does not apply.

How to fix CVE-2026-91189

  • No stored fix

    No vendor fix text is stored. Use the linked advisory before you change production.

  • Version check

    No version range is stored, so an installed version cannot be checked on this page.

  • Advisory

    Open the cve_org record and follow its fix.

  • Official advisories

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-91189. EPSS is 0.14%. Act only if a listed version of The GUIX binary resource is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-190: Integer Overflow; CWE-680; CWE-787: Out-of-bounds Write. EPSS 0.14%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 20, 2026 · NIST NVD

    Detected

    The GUIX binary resource loader never checks that a font page's glyph range is well formed. and are read verbatim from the file and only the upper bound of is validated, so a page declaring makes 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

  2. Oct 20, 2026 · NIST NVD

    Updated

    The GUIX binary resource loader never checks that a font page's glyph range is well formed. and are read verbatim from the file and only the upper bound of is validated, so a page declaring makes 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

  3. Oct 20, 2026 · NIST NVD

    Updated

    The GUIX binary resource loader never checks that a font page's glyph range is well formed. and are read verbatim from the file and only the upper bound of is validated, so a page declaring makes 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

Sources

  • CVE.orgVulnerability recordCVE-2026-91189

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-91189

    30-day exploitation probability 0.14%

    first.org
  • NIST NVDVulnerability recordCVE-2026-91189

    The GUIX binary resource loader never checks that a font page's glyph range is well formed. and are read verbatim from the file and only the upper bound of is validated, so a page declaring `first_glyph > last_

    nvd.nist.gov

References

Freshness

Last verified in this catalog Nov 7, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSOct 23, 2026
  • CVE.orgOct 21, 2026
  • NIST NVDOct 21, 2026