Type Confusion in Lexbor Fragment Parser
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- Present
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-843 and the CVSS impact.
Summary
Lexbor is a web browser engine library. Prior to 2.7.0, a type‑confusion vulnerability exists in Lexbor’s HTML fragment parser. When ns = UNDEF, a comment is created using the “unknown element” constructor. The comment’s data are written into the element’s fields via an unsafe cast, corrupting the qualified_name field. That corrupted value is later used as a pointer and dereferenced near the zero page. This vulnerability is fixed in 2.7.0.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- 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
- Fix · CNA lexbor (lexbor) Fixed in 2.7.0
Timeline
- 2026-10-02 Threatist record created from CVE-2026-29079
References
More Lexbor vulnerabilities
- TI-2026-23223 Integer Underflow in Lexbor ISO‑2022‑JP Encoder CVSS 4.0HIGH 8.2
Sources
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences