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Fencer Intel
high 7.8

CVE-2026-88052 json

Tesseract: Heap out-of-bounds write in UNICHARSET::load_via_fgets via count/insert desynchronization

published 2mo ago modified last mo. also EUVD-2026-75629 , GHSA-2hm8-q5c7-c373

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
7.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 7%
public exploits
0
none known

Summary

Tesseract is an open source OCR engine. In version 5.5.3 and earlier, UNICHARSET::load_via_fgets in src/ccutil/unicharset.cpp trusts the declared unichar count as a loop bound and uses id as an unchecked index into the unichars vector. unichar_insert_backwards_compatible can leave the vector unchanged for an empty, duplicate, or already-encodable representation, causing id to become larger than unichars.size(). Subsequent set_* calls and the write to unichars[id].properties.enabled then write UNICHAR_PROPERTIES beyond the vector during initialization in both the default LSTM and legacy engines, causing heap corruption, a crash, or potentially controlled corruption. No fixed release is available as of this review.

Patch / fix

  • tesseract Ubuntu Pro 14.04 LTS 3.03.02-3ubuntu0.1~esm1
  • tesseract Ubuntu Pro 16.04 LTS 3.04.01-4ubuntu0.1~esm1
  • 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-2026-88052

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-2026-88052 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-2026-88052 updated cvss 7.8

tesseract: Tesseract: Heap out-of-bounds write can lead to arbitrary code execution

  • 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
none
Automatable
no
Technical impact
total
Assessed
2mo ago

Exploit prediction

0.17% chance of exploitation in the next 30 days, higher than 7% of all scored CVEs (FIRST EPSS, 2026-11-11).

Exploits and checks

  • github.com https://github.com/tesseract-ocr/tesseract/security/advisories/GHSA-2hm8-q5c7-c373 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected products

  • tesseract-ocr tesseract

Classification

Weakness
  • CWE-129 Improper Validation of Array Index
  • CWE-787 Out-of-bounds Write

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.