Divide by zero in libschrift font handling crashes applications
Key facts
- Attack vector
- Local
- Privileges required
- None
- User interaction
- Passive
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- No fix listed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-369.
Summary
libschrift through 0.10.2 divides by zero when a font's unitsPerEm value in the head table is 0 (CWE-369). A local attacker who gets a user to open a crafted TrueType font can crash applications that render it.
Written with Claude Haiku 5.5 from the sources below · 2026-10-28
Description from the CNA
libschrift through 0.10.2 contains a divide by zero vulnerability that allows attackers to crash applications by supplying a font with unitsPerEm of 0 in the head table. Attackers can provide a crafted TrueType font whose NaN glyph coordinates bypass clip_points(), causing an out-of-bounds raster read in draw_line() during sft_render() and crashing the process.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
The sources list no fixed version for libschrift.
Written with Claude Haiku 5.5 from the sources below · 2026-10-28
Timeline
- 2026-10-14 Threatist record created from CVE-2026-110605
- 2026-10-14 Alias added: GHSA-h8w2-cf8p-7p38
- 2026-10-16 Priority changed: MEDIUM → LOW
- 2026-10-26 CISA SSVC decision points changed
- 2026-10-26 Priority changed: LOW → MEDIUM
References
Sources
- CVE-2026-110605 · CVE Program
- CVE-2026-110605 · NVD
- FIRST EPSS
- GHSA-h8w2-cf8p-7p38 · GitHub Advisory Database · CC BY 4.0
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