Vulnerability · Published Sep 10, 2026 · Assigned by GitHub_M
CVE-2026-88049Tesseract: Heap out-of-bounds write in LSTM::Forward via na_/gate-matrix dimension mismatch
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 0.1% (higher than 4% 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, prior .traineddata hardening added bounds checks to NetworkIO::CopyTimeStepGeneral and NetworkIO::Randomize in src/lstm/networkio.cpp but left NetworkIO::WriteTimeStepPart and NetworkIO::AddTimeStepPart unchecked. In LSTM::Forward in src/lstm/lstm.cpp, source_ is sized from the independently deserialized na_ field while the WriteTimeStepPart count is ns_, which comes from the CI gate WeightMatrix dim1() value. A crafted NT_LSTM layer can make ns_ much larger than na_, causing a heap out-of-bounds write during the first recognition step on the default LSTM engine and 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-2026-88049 |
| Debian:13 | tesseract | no fix listed | DEBIAN-CVE-2026-88049 |
| Debian:14 | tesseract | no fix listed | DEBIAN-CVE-2026-88049 |
| 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-2026-88049 |
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