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Fencer Vulns
high 7.8

CVE-2026-88052 json

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

published 2026-09-10 59 d ago modified 2026-09-16 53 d ago also EUVD-2026-75629

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 6%
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 8 4.1.1-7.el8_10
  • tesseract Rocky Linux 9 4.1.1-11.el9_8
  • tesseract Rocky Linux 10 5.3.4-11.el10_2

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

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
    fixed: vendor fix RHSA-2026:95086
  • Red Hat Enterprise Linux AppStream (v. 10) tesseract 5.3.4-11.el10_2
    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-debuginfo 4.1.1-11.el9_8, tesseract-debugsource 4.1.1-11.el9_8, tesseract-tools-debuginfo 4.1.1-11.el9_8
    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-debuginfo 5.3.4-11.el10_2, tesseract-debugsource 5.3.4-11.el10_2, tesseract-tools-debuginfo 5.3.4-11.el10_2
    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
58 d ago

Exploit prediction

0.17% chance of exploitation in the next 30 days, higher than 6% of all scored CVEs (FIRST EPSS, 2026-11-08).

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 Vulns 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.