CVE-2026-23951 (GCVE-0-2026-23951)
Vulnerability from cvelistv5 – Published: 2026-01-22 00:17 – Updated: 2026-01-22 21:44
VLAI
EPSS
VEX
Title
SumatraPDF's Integer Underflow in PalmDbReader Leads to Crash
Summary
SumatraPDF is a multi-format reader for Windows. All versions contain an off-by-one error in the validation code that only triggers with exactly 2 records, causing an integer underflow in the size calculation. This bug exists in PalmDbReader::GetRecord when opening a crafted Mobi file, resulting in an out-of-bounds heap read that crashes the app. There are no published fixes at the time of publication.
Severity
5.5 (Medium)
SSVC
Exploitation: poc
Automatable: no
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-01-22 21:44 UTC
Assigner
References
2 references
| URL | Tags |
|---|---|
| https://github.com/sumatrapdfreader/sumatrapdf/se… | x_refsource_CONFIRM |
| https://github.com/sumatrapdfreader/sumatrapdf/bl… | x_refsource_MISC |
Impacted products
1 product
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| sumatrapdfreader | sumatrapdf |
Affected:
<= 3.5.2rel
|
guessed |
{
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2026-23951",
"options": [
{
"Exploitation": "poc"
},
{
"Automatable": "no"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-01-22T21:44:16.346671Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-01-22T21:44:27.284Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"product": "sumatrapdf",
"vendor": "sumatrapdfreader",
"versions": [
{
"status": "affected",
"version": "\u003c= 3.5.2rel"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "SumatraPDF is a multi-format reader for Windows. All versions contain an off-by-one error in the validation code that only triggers with exactly 2 records, causing an integer underflow in the size calculation. This bug exists in PalmDbReader::GetRecord when opening a crafted Mobi file, resulting in an out-of-bounds heap read that crashes the app. There are no published fixes at the time of publication."
}
],
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "LOCAL",
"availabilityImpact": "HIGH",
"baseScore": 5.5,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "REQUIRED",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H",
"version": "3.1"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-125",
"description": "CWE-125: Out-of-bounds Read",
"lang": "en",
"type": "CWE"
}
]
},
{
"descriptions": [
{
"cweId": "CWE-191",
"description": "CWE-191: Integer Underflow (Wrap or Wraparound)",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-01-22T00:17:10.159Z",
"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"shortName": "GitHub_M"
},
"references": [
{
"name": "https://github.com/sumatrapdfreader/sumatrapdf/security/advisories/GHSA-hj4w-c5x8-p2hv",
"tags": [
"x_refsource_CONFIRM"
],
"url": "https://github.com/sumatrapdfreader/sumatrapdf/security/advisories/GHSA-hj4w-c5x8-p2hv"
},
{
"name": "https://github.com/sumatrapdfreader/sumatrapdf/blob/master/src/PalmDbReader.cpp",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/sumatrapdfreader/sumatrapdf/blob/master/src/PalmDbReader.cpp"
}
],
"source": {
"advisory": "GHSA-hj4w-c5x8-p2hv",
"discovery": "UNKNOWN"
},
"title": "SumatraPDF\u0027s Integer Underflow in PalmDbReader Leads to Crash"
}
},
"cveMetadata": {
"assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"assignerShortName": "GitHub_M",
"cveId": "CVE-2026-23951",
"datePublished": "2026-01-22T00:17:10.159Z",
"dateReserved": "2026-01-19T14:49:06.312Z",
"dateUpdated": "2026-01-22T21:44:27.284Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"epss": {
"cve": "CVE-2026-23951",
"date": "2026-09-27",
"epss": "0.00224",
"percentile": "0.11723"
},
"nvd": {
"cve": {
"affected": [
{
"affectedData": [
{
"product": "sumatrapdf",
"vendor": "sumatrapdfreader",
"versions": [
{
"status": "affected",
"version": "\u003c= 3.5.2rel"
}
]
}
],
"source": "security-advisories@github.com"
}
],
"configurations": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:a:sumatrapdfreader:sumatrapdf:-:*:*:*:*:*:*:*",
"matchCriteriaId": "EDC837AF-B0DA-4A27-8CF4-EE8846526B37",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "SumatraPDF is a multi-format reader for Windows. All versions contain an off-by-one error in the validation code that only triggers with exactly 2 records, causing an integer underflow in the size calculation. This bug exists in PalmDbReader::GetRecord when opening a crafted Mobi file, resulting in an out-of-bounds heap read that crashes the app. There are no published fixes at the time of publication."
},
{
"lang": "es",
"value": "SumatraPDF es un lector multiformato para Windows. Todas las versiones contienen un error de off-by-one en el c\u00f3digo de validaci\u00f3n que solo se activa con exactamente 2 registros, causando un subdesbordamiento de enteros en el c\u00e1lculo del tama\u00f1o. Este error existe en PalmDbReader::GetRecord al abrir un archivo Mobi manipulado, resultando en una lectura de mont\u00f3n fuera de l\u00edmites que bloquea la aplicaci\u00f3n. No hay correcciones publicadas en el momento de la publicaci\u00f3n."
}
],
"id": "CVE-2026-23951",
"lastModified": "2026-06-17T10:22:20.423",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "LOCAL",
"availabilityImpact": "HIGH",
"baseScore": 5.5,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "REQUIRED",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H",
"version": "3.1"
},
"exploitabilityScore": 1.8,
"impactScore": 3.6,
"source": "security-advisories@github.com",
"type": "Secondary"
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-23951",
"options": [
{
"exploitation": "poc"
},
{
"automatable": "no"
},
{
"technicalImpact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-01-22T21:44:16.346671Z",
"version": "2.0.3"
}
}
]
},
"published": "2026-01-22T01:15:52.633",
"references": [
{
"source": "security-advisories@github.com",
"tags": [
"Product"
],
"url": "https://github.com/sumatrapdfreader/sumatrapdf/blob/master/src/PalmDbReader.cpp"
},
{
"source": "security-advisories@github.com",
"tags": [
"Exploit",
"Vendor Advisory"
],
"url": "https://github.com/sumatrapdfreader/sumatrapdf/security/advisories/GHSA-hj4w-c5x8-p2hv"
}
],
"sourceIdentifier": "security-advisories@github.com",
"vulnStatus": "Analyzed",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-125"
},
{
"lang": "en",
"value": "CWE-191"
}
],
"source": "security-advisories@github.com",
"type": "Secondary"
},
{
"description": [
{
"lang": "en",
"value": "CWE-193"
}
],
"source": "nvd@nist.gov",
"type": "Primary"
}
]
}
},
"redhat_vex": {
"current_release_date": "2026-01-23T00:26:36+00:00",
"cve": "CVE-2026-23951",
"id": "CVE-2026-23951",
"initial_release_date": "2026-01-01T00:00:00+00:00",
"product_status:known_not_affected": "1",
"source": "Red Hat CSAF VEX",
"status": "final",
"title": "SumatraPDF\u0027s Integer Underflow in PalmDbReader Leads to Crash",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-23951.json",
"version": "3"
},
"vulnrichment": {
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2026-23951",
"options": [
{
"Exploitation": "poc"
},
{
"Automatable": "no"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-01-22T21:44:16.346671Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-01-22T21:44:22.321Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"product": "sumatrapdf",
"vendor": "sumatrapdfreader",
"versions": [
{
"status": "affected",
"version": "\u003c= 3.5.2rel"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "SumatraPDF is a multi-format reader for Windows. All versions contain an off-by-one error in the validation code that only triggers with exactly 2 records, causing an integer underflow in the size calculation. This bug exists in PalmDbReader::GetRecord when opening a crafted Mobi file, resulting in an out-of-bounds heap read that crashes the app. There are no published fixes at the time of publication."
}
],
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "LOCAL",
"availabilityImpact": "HIGH",
"baseScore": 5.5,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "REQUIRED",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H",
"version": "3.1"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-125",
"description": "CWE-125: Out-of-bounds Read",
"lang": "en",
"type": "CWE"
}
]
},
{
"descriptions": [
{
"cweId": "CWE-191",
"description": "CWE-191: Integer Underflow (Wrap or Wraparound)",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-01-22T00:17:10.159Z",
"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"shortName": "GitHub_M"
},
"references": [
{
"name": "https://github.com/sumatrapdfreader/sumatrapdf/security/advisories/GHSA-hj4w-c5x8-p2hv",
"tags": [
"x_refsource_CONFIRM"
],
"url": "https://github.com/sumatrapdfreader/sumatrapdf/security/advisories/GHSA-hj4w-c5x8-p2hv"
},
{
"name": "https://github.com/sumatrapdfreader/sumatrapdf/blob/master/src/PalmDbReader.cpp",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/sumatrapdfreader/sumatrapdf/blob/master/src/PalmDbReader.cpp"
}
],
"source": {
"advisory": "GHSA-hj4w-c5x8-p2hv",
"discovery": "UNKNOWN"
},
"title": "SumatraPDF\u0027s Integer Underflow in PalmDbReader Leads to Crash"
}
},
"cveMetadata": {
"assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"assignerShortName": "GitHub_M",
"cveId": "CVE-2026-23951",
"datePublished": "2026-01-22T00:17:10.159Z",
"dateReserved": "2026-01-19T14:49:06.312Z",
"dateUpdated": "2026-01-22T21:44:27.284Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
}
}
Loading…
Loading…
Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Loading…
Loading…
The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
Loading…
Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
Loading…