HighFix available
tesseract — security advisory
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.
- Products
- tesseract
- Affected versions
- 3.04.01-6, 3.04.01-6build1, 3.04.01-6build2, 4.00~git2188-cdc35338-4build1, 4.00~git2188-cdc35338-5, 4.00~git2207-766b7bd6-3.1, 4.00~git2219-40f43111-1.2, 4.00~git2288-10f4998a-2, 4.1.0-1, 4.1.0-2, 4.1.1-1, 4.1.1-2, 4.1.1-2.1, 4.1.1-2.1build1, 4.1.1-2build1, 4.1.1-2build2, 5.3.0-2build1, 5.3.3-1, 5.3.3-1build1, 5.3.4-1, 5.3.4-1build3, 5.3.4-1build4, 5.3.4-1build5, 5.5.0-1, 5.5.0-1.1, 5.5.0-1build1
- Fixed versions
- 4.00~git2288-10f4998a-2ubuntu0.1~esm1, 4.1.1-2.1ubuntu0.1~esm1, 4.1.1-2ubuntu0.1~esm1, 5.3.4-1ubuntu0.1~esm1, 5.5.0-1ubuntu0.1~esm1
- CVEs
- CVE-2026-88049
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 03:29 UTC · Revision 1
Source evidence
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.
osv:UBUNTU-CVE-2026-88049
tesseract
Fixed versions: 4.00~git2288-10f4998a-2ubuntu0.1~esm1
tesseract
Fixed versions: 4.1.1-2ubuntu0.1~esm1
tesseract
Fixed versions: 4.1.1-2.1ubuntu0.1~esm1
tesseract
Fixed versions: 5.3.4-1ubuntu0.1~esm1
tesseract
Fixed versions: Not specified
tesseract
Fixed versions: 5.5.0-1ubuntu0.1~esm1
Complete source record
{
"id": "55bb94acdfb72fe4cdc46094c0a846ba70add1779e8b18c99f77452f7ff6d96c",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-88049",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2026-88049",
"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.",
"evidence": "osv:UBUNTU-CVE-2026-88049",
"products": [
{
"name": {
"value": "tesseract",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "4.00~git2288-10f4998a-2ubuntu0.1~esm1",
"evidence": "/affected/0/ranges"
}
],
"affected_versions": [
{
"value": "3.04.01-6",
"evidence": "/affected/0/versions"
},
{
"value": "3.04.01-6build1",
"evidence": "/affected/0/versions"
},
{
"value": "3.04.01-6build2",
"evidence": "/affected/0/versions"
},
{
"value": "4.00~git2188-cdc35338-4build1",
"evidence": "/affected/0/versions"
},
{
"value": "4.00~git2188-cdc35338-5",
"evidence": "/affected/0/versions"
},
{
"value": "4.00~git2207-766b7bd6-3.1",
"evidence": "/affected/0/versions"
},
{
"value": "4.00~git2219-40f43111-1.2",
"evidence": "/affected/0/versions"
},
{
"value": "4.00~git2288-10f4998a-2",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
"value": "tesseract",
"evidence": "/affected/1/package/name"
},
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{
"value": "4.1.1-2ubuntu0.1~esm1",
"evidence": "/affected/1/ranges"
}
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"affected_versions": [
{
"value": "4.1.0-1",
"evidence": "/affected/1/versions"
},
{
"value": "4.1.0-2",
"evidence": "/affected/1/versions"
},
{
"value": "4.1.1-1",
"evidence": "/affected/1/versions"
},
{
"value": "4.1.1-2",
"evidence": "/affected/1/versions"
},
{
"value": "4.1.1-2build1",
"evidence": "/affected/1/versions"
},
{
"value": "4.1.1-2build2",
"evidence": "/affected/1/versions"
}
]
},
{
"name": {
"value": "tesseract",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
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{
"value": "4.1.1-2.1ubuntu0.1~esm1",
"evidence": "/affected/2/ranges"
}
],
"affected_versions": [
{
"value": "4.1.1-2.1",
"evidence": "/affected/2/versions"
},
{
"value": "4.1.1-2.1build1",
"evidence": "/affected/2/versions"
}
]
},
{
"name": {
"value": "tesseract",
"evidence": "/affected/3/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "5.3.4-1ubuntu0.1~esm1",
"evidence": "/affected/3/ranges"
}
],
"affected_versions": [
{
"value": "5.3.0-2build1",
"evidence": "/affected/3/versions"
},
{
"value": "5.3.3-1",
"evidence": "/affected/3/versions"
},
{
"value": "5.3.3-1build1",
"evidence": "/affected/3/versions"
},
{
"value": "5.3.4-1",
"evidence": "/affected/3/versions"
},
{
"value": "5.3.4-1build3",
"evidence": "/affected/3/versions"
},
{
"value": "5.3.4-1build4",
"evidence": "/affected/3/versions"
},
{
"value": "5.3.4-1build5",
"evidence": "/affected/3/versions"
}
]
},
{
"name": {
"value": "tesseract",
"evidence": "/affected/4/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "5.5.0-1build1",
"evidence": "/affected/4/versions"
},
{
"value": "5.5.0-1.1",
"evidence": "/affected/4/versions"
}
]
},
{
"name": {
"value": "tesseract",
"evidence": "/affected/5/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "5.5.0-1ubuntu0.1~esm1",
"evidence": "/affected/5/ranges"
}
],
"affected_versions": [
{
"value": "5.5.0-1",
"evidence": "/affected/5/versions"
},
{
"value": "5.5.0-1build1",
"evidence": "/affected/5/versions"
}
]
}
],
"severity": "high",
"structured": {
"id": "UBUNTU-CVE-2026-88049",
"aliases": [
"UBUNTU-CVE-2026-88049"
],
"metrics": [
{
"type": "CVSS_V4",
"score": "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"
},
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
},
{
"type": "Ubuntu",
"score": "medium"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "4.00~git2288-10f4998a-2ubuntu0.1~esm1"
}
]
}
],
"package": {
"name": "tesseract",
"purl": "pkg:deb/ubuntu/tesseract?arch=source&distro=esm-apps%2Fbionic",
"ecosystem": "Ubuntu:Pro:18.04:LTS"
},
"versions": [
"3.04.01-6",
"3.04.01-6build1",
"3.04.01-6build2",
"4.00~git2188-cdc35338-4build1",
"4.00~git2188-cdc35338-5",
"4.00~git2207-766b7bd6-3.1",
"4.00~git2219-40f43111-1.2",
"4.00~git2288-10f4998a-2"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-88049.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libtesseract4",
"binary_version": "4.00~git2288-10f4998a-2ubuntu0.1~esm1"
},
{
"binary_name": "tesseract-ocr",
"binary_version": "4.00~git2288-10f4998a-2ubuntu0.1~esm1"
},
{
"binary_name": "tesseract-ocr-all",
"binary_version": "4.00~git2288-10f4998a-2ubuntu0.1~esm1"
}
],
"availability": "Available with Ubuntu Pro: https://ubuntu.com/pro"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "4.1.1-2ubuntu0.1~esm1"
}
]
}
],
"package": {
"name": "tesseract",
"purl": "pkg:deb/ubuntu/tesseract?arch=source&distro=esm-apps%2Ffocal",
"ecosystem": "Ubuntu:Pro:20.04:LTS"
},
"versions": [
"4.1.0-1",
"4.1.0-2",
"4.1.1-1",
"4.1.1-2",
"4.1.1-2build1",
"4.1.1-2build2"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-88049.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libtesseract4",
"binary_version": "4.1.1-2ubuntu0.1~esm1"
},
{
"binary_name": "tesseract-ocr",
"binary_version": "4.1.1-2ubuntu0.1~esm1"
},
{
"binary_name": "tesseract-ocr-all",
"binary_version": "4.1.1-2ubuntu0.1~esm1"
}
],
"availability": "Available with Ubuntu Pro: https://ubuntu.com/pro"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "4.1.1-2.1ubuntu0.1~esm1"
}
]
}
],
"package": {
"name": "tesseract",
"purl": "pkg:deb/ubuntu/tesseract?arch=source&distro=esm-apps%2Fjammy",
"ecosystem": "Ubuntu:Pro:22.04:LTS"
},
"versions": [
"4.1.1-2.1",
"4.1.1-2.1build1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-88049.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libtesseract4",
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{
"binary_name": "tesseract-ocr",
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{
"binary_name": "tesseract-ocr-all",
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}
},
{
"ranges": [
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]
}
],
"package": {
"name": "tesseract",
"purl": "pkg:deb/ubuntu/tesseract?arch=source&distro=esm-apps%2Fnoble",
"ecosystem": "Ubuntu:Pro:24.04:LTS"
},
"versions": [
"5.3.0-2build1",
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"5.3.4-1",
"5.3.4-1build3",
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"binaries": [
{
"binary_name": "libtesseract5",
"binary_version": "5.3.4-1ubuntu0.1~esm1"
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{
"binary_name": "tesseract-ocr",
"binary_version": "5.3.4-1ubuntu0.1~esm1"
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{
"binary_name": "tesseract-ocr-all",
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],
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},
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],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-88049.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libtesseract5",
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{
"binary_name": "tesseract-ocr",
"binary_version": "5.5.0-1.1"
},
{
"binary_name": "tesseract-ocr-all",
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]
}
},
{
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{
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],
"package": {
"name": "tesseract",
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},
"versions": [
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],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-88049.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libtesseract5",
"binary_version": "5.5.0-1ubuntu0.1~esm1"
},
{
"binary_name": "tesseract-ocr",
"binary_version": "5.5.0-1ubuntu0.1~esm1"
},
{
"binary_name": "tesseract-ocr-all",
"binary_version": "5.5.0-1ubuntu0.1~esm1"
}
],
"availability": "Available with Ubuntu Pro: https://ubuntu.com/pro"
}
}
],
"modified": "2026-10-17T13:01:15.178454115Z",
"provider": "osv",
"upstream": [
"CVE-2026-88049"
],
"references": [
"https://ubuntu.com/security/CVE-2026-88049",
"https://www.cve.org/CVERecord?id=CVE-2026-88049",
"https://ubuntu.com/security/notices/USN-8882-1"
]
},
"related_cves": [
{
"value": "CVE-2026-88049",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 361376,
"published_at": "2026-09-10T17:17:00+00:00"
}