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Fencer Intel
medium 5.5

CVE-2026-88049 json

Tesseract: Heap out-of-bounds write in LSTM::Forward via na_/gate-matrix dimension mismatch

published 2mo ago modified last mo. also EUVD-2026-75592 , GHSA-jgq8-pprg-vc68

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository tesseract-ocr/tesseract. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 4%
public exploits
0
none known

Summary

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.

Patch / fix

  • tesseract Ubuntu Pro 18.04 LTS 4.00~git2288-10f4998a-2ubuntu0.1~esm1
  • tesseract Ubuntu Pro 20.04 LTS 4.1.1-2ubuntu0.1~esm1
  • tesseract Ubuntu Pro 22.04 LTS 4.1.1-2.1ubuntu0.1~esm1
  • tesseract Ubuntu Pro 24.04 LTS 5.3.4-1ubuntu0.1~esm1
  • tesseract Ubuntu Pro 26.04 LTS 5.5.0-1ubuntu0.1~esm1

ubuntu advisories UBUNTU-CVE-2026-88049

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • tesseract-ocr openSUSE Leap 16.0 5.5.3-bp160.1.1
  • tesseract-ocr openSUSE Tumbleweed 5.5.3-2.1

opensuse advisories openSUSE-SU-2026:21957-1openSUSE-SU-2026:11887-1

  • tesseract AlmaLinux 8 4.1.1-7.el8_10
  • tesseract AlmaLinux 10 5.3.4-11.el10_2

almalinux advisories ALSA-2026:95725ALSA-2026:95085

  • tesseract Rocky Linux 9 4.1.1-11.el9_8
  • tesseract Rocky Linux 8 4.1.1-7.el8_10
  • tesseract Rocky Linux 10 5.3.4-11.el10_2

rocky linux advisories RLSA-2026:98514RLSA-2026:95725RLSA-2026:95086RLSA-2026:95085

Is CVE-2026-88049 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-88049 updated cvss 7.8

tesseract: Tesseract: Heap out-of-bounds write allows arbitrary code execution or denial of service

  • Red Hat Enterprise Linux AppStream (v. 8) tesseract 4.1.1-7.el8_10
    fixed: vendor fix RHSA-2026:95725
  • Red Hat Enterprise Linux AppStream (v. 9) tesseract 4.1.1-11.el9_8, tesseract 4.1.1-11.el9_9
    fixed: vendor fix RHSA-2026:95086
  • Red Hat Enterprise Linux AppStream (v. 10) tesseract 5.3.4-11.el10_2, tesseract 5.3.4-11.el10_3
    fixed: vendor fix RHSA-2026:95085
  • Red Hat Enterprise Linux AppStream AUS (v.8.6) tesseract 4.1.1-2.el8_6.3
    fixed: vendor fix RHSA-2026:96239
  • Red Hat Enterprise Linux AppStream E4S (v.8.8) tesseract 4.1.1-2.el8_8.3
    fixed: vendor fix RHSA-2026:96238
  • Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6) tesseract 4.1.1-2.el8_6.3
    fixed: vendor fix RHSA-2026:96239
  • Red Hat Enterprise Linux AppStream TUS (v.8.8) tesseract 4.1.1-2.el8_8.3
    fixed: vendor fix RHSA-2026:96238
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) tesseract-devel 4.1.1-11.el9_8, tesseract-devel 4.1.1-11.el9_9, tesseract-debuginfo 4.1.1-11.el9_8, tesseract-debuginfo 4.1.1-11.el9_9, tesseract-debugsource 4.1.1-11.el9_8, tesseract-debugsource 4.1.1-11.el9_9, +2 more
    fixed: vendor fix RHSA-2026:95086
show 2 more
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) tesseract-devel 5.3.4-11.el10_2, tesseract-devel 5.3.4-11.el10_3, tesseract-debuginfo 5.3.4-11.el10_2, tesseract-debuginfo 5.3.4-11.el10_3, tesseract-debugsource 5.3.4-11.el10_2, tesseract-debugsource 5.3.4-11.el10_3, +2 more
    fixed: vendor fix RHSA-2026:95085
  • Red Hat Enterprise Linux CRB (v. 8) tesseract-devel 4.1.1-7.el8_10, tesseract-debuginfo 4.1.1-7.el8_10, tesseract-debugsource 4.1.1-7.el8_10
    fixed: vendor fix RHSA-2026:95725

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
2mo ago

Exploit prediction

0.15% chance of exploitation in the next 30 days, higher than 4% of all scored CVEs (FIRST EPSS, 2026-11-11).

Exploits and checks

  • github.com https://github.com/tesseract-ocr/tesseract/security/advisories/GHSA-jgq8-pprg-vc68 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 8.6 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
CNA 4.0 8.6 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

  • tesseract-ocr tesseract

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

The maintainers of tesseract-ocr/tesseract published their own advisory on GitHub. Reviewed sources take precedence over it.