Tesseract is an open source OCR engine. From 5.4.0 until 5.5.4, AppendLinePolygon in src/api/pagerenderer.cpp destroys the caller-owned right-to-left Pta accumulator while receiving it by value, leaving line_top_rtl_pts and line_bottom_rtl_pts dangling. On an upright Hebrew or Arabic page at the default PAGE XML level, POLYGONFLAG with a false skewed_flag enters the vulnerable calls, while LEVELFLAG greater than zero provides an alternative gate.
The calls repeatedly read and free the stale object, causing a double free and use after free and allowing corrupted coordinates to reach RecalcPolygonline. This issue is fixed in version 5.5.4.
Attack Parameters
Attack Vector
Local
Requires local access
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
None
No privileges needed
User Interaction
Passive
Minimal interaction
Impact Assessment
Confidentiality
Low
Partial data leak
Integrity
Low
Partial data modification
Availability
High
Complete denial of service
CVSS Vector v4.0
Weakness Type (CWE)
References 4
https://github.com/tesseract-ocr/tesseract/commit/fa52414ff1fd13ae4b00048d2498f…
security-advisories@github.com
https://github.com/tesseract-ocr/tesseract/pull/4647
security-advisories@github.com
https://github.com/tesseract-ocr/tesseract/releases/tag/5.5.4
security-advisories@github.com
https://github.com/tesseract-ocr/tesseract/security/advisories/GHSA-vf7v-2h4f-6…
security-advisories@github.com