Vulnerability · Published Sep 10, 2026 · Assigned by GitHub_M
CVE-2026-88053Tesseract: Heap out-of-bounds write in Classify::ReadIntTemplates via unvalidated counts in crafted .traineddata
High 8.6
In plain English
A high-severity out-of-bounds write in tesseract from tesseract-ocr. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 7% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
Tesseract is an open source OCR engine. In version 5.5.3 and earlier, Classify::ReadIntTemplates in src/classify/intproto.cpp reads NumClassPruners, NumClasses, and NumProtoSets from the TESSDATA_INTTEMP component of a crafted .traineddata file and uses those values as loop bounds without validating them against MAX_NUM_CLASS_PRUNERS, MAX_NUM_CLASSES, and MAX_NUM_PROTO_SETS. The loops store heap pointers into fixed-capacity ClassPruners and ProtoSets arrays in INT_TEMPLATES_STRUCT and INT_CLASS_STRUCT, so an oversized count causes heap out-of-bounds pointer writes during legacy-classifier initialization before OCR begins, resulting in heap corruption, a crash, or potentially controlled corruption. No fixed release is available as of this review.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:10 | tesseract | 5.3.4-11.el10_2 | ALSA-2026:95085 |
| AlmaLinux:8 | tesseract | 4.1.1-7.el8_10 | ALSA-2026:95725 |
| AlmaLinux:10 | tesseract-devel | 5.3.4-11.el10_2 | ALSA-2026:95085 |
| AlmaLinux:8 | tesseract-devel | 4.1.1-7.el8_10 | ALSA-2026:95725 |
| AlmaLinux:9 | tesseract-devel | 4.1.1-11.el9_8 | ALSA-2026:95086 |
| Debian:12 | tesseract | no fix listed | DEBIAN-CVE-2026-88053 |
| Debian:13 | tesseract | no fix listed | DEBIAN-CVE-2026-88053 |
| Debian:14 | tesseract | no fix listed | DEBIAN-CVE-2026-88053 |
| Rocky Linux:10 | tesseract | 0:5.3.4-11.el10_2 | RLSA-2026:95085 |
| Rocky Linux:9 | tesseract | 0:4.1.1-11.el9_8 | RLSA-2026:95086 |
| Ubuntu:26.10 | tesseract | no fix listed | UBUNTU-CVE-2026-88053 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| tesseract-ocr | tesseract | <= 5.5.3 |
Weakness: CWE-787 · Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N