CVE-2026-82398 (GCVE-0-2026-82398)
Vulnerability from cvelistv5 – Published: 2026-08-31 21:41 – Updated: 2026-08-31 21:41
VLAI
EPSS
VEX
Title
pypdf: Inefficient handling of non-whitespace inputs in read_until_whitespace
Summary
pypdf is a free and open-source pure-python PDF library. Prior to 6.15.0, an attacker can craft a PDF that causes long runtimes when the pypdf/_utils.py function read_until_whitespace reads a stream containing a long run of bytes without whitespace. The function repeatedly performs immutable bytes concatenation in a one-byte loop, causing quadratic processing cost for the long non-whitespace input. This issue is fixed in version 6.15.0.
Severity
CWE
- CWE-407 - Inefficient Algorithmic Complexity
Assigner
References
4 references
| URL | Tags |
|---|---|
| https://github.com/py-pdf/pypdf/security/advisori… | x_refsource_CONFIRM |
| https://github.com/py-pdf/pypdf/pull/3947 | x_refsource_MISC |
| https://github.com/py-pdf/pypdf/commit/4959848e05… | x_refsource_MISC |
| https://github.com/py-pdf/pypdf/releases/tag/6.15.0 | x_refsource_MISC |
Impacted products
{
"containers": {
"cna": {
"affected": [
{
"product": "pypdf",
"vendor": "py-pdf",
"versions": [
{
"status": "affected",
"version": "\u003c 6.15.0"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "pypdf is a free and open-source pure-python PDF library. Prior to 6.15.0, an attacker can craft a PDF that causes long runtimes when the pypdf/_utils.py function read_until_whitespace reads a stream containing a long run of bytes without whitespace. The function repeatedly performs immutable bytes concatenation in a one-byte loop, causing quadratic processing cost for the long non-whitespace input. This issue is fixed in version 6.15.0."
}
],
"metrics": [
{
"cvssV4_0": {
"attackComplexity": "LOW",
"attackRequirements": "NONE",
"attackVector": "NETWORK",
"baseScore": 6.9,
"baseSeverity": "MEDIUM",
"privilegesRequired": "NONE",
"subAvailabilityImpact": "NONE",
"subConfidentialityImpact": "NONE",
"subIntegrityImpact": "NONE",
"userInteraction": "NONE",
"vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N",
"version": "4.0",
"vulnAvailabilityImpact": "LOW",
"vulnConfidentialityImpact": "NONE",
"vulnIntegrityImpact": "NONE"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-407",
"description": "CWE-407: Inefficient Algorithmic Complexity",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-31T21:41:10.272Z",
"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"shortName": "GitHub_M"
},
"references": [
{
"name": "https://github.com/py-pdf/pypdf/security/advisories/GHSA-fc8x-2rww-xw9m",
"tags": [
"x_refsource_CONFIRM"
],
"url": "https://github.com/py-pdf/pypdf/security/advisories/GHSA-fc8x-2rww-xw9m"
},
{
"name": "https://github.com/py-pdf/pypdf/pull/3947",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/py-pdf/pypdf/pull/3947"
},
{
"name": "https://github.com/py-pdf/pypdf/commit/4959848e057e37c218dccad7465259210923faaa",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/py-pdf/pypdf/commit/4959848e057e37c218dccad7465259210923faaa"
},
{
"name": "https://github.com/py-pdf/pypdf/releases/tag/6.15.0",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/py-pdf/pypdf/releases/tag/6.15.0"
}
],
"source": {
"advisory": "GHSA-fc8x-2rww-xw9m",
"discovery": "UNKNOWN"
},
"title": "pypdf: Inefficient handling of non-whitespace inputs in read_until_whitespace"
}
},
"cveMetadata": {
"assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"assignerShortName": "GitHub_M",
"cveId": "CVE-2026-82398",
"datePublished": "2026-08-31T21:41:10.272Z",
"dateReserved": "2026-08-28T22:00:43.512Z",
"dateUpdated": "2026-08-31T21:41:10.272Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"nvd": "{\"cve\":{\"id\":\"CVE-2026-82398\",\"sourceIdentifier\":\"security-advisories@github.com\",\"published\":\"2026-08-31T22:17:23.083\",\"lastModified\":\"2026-08-31T22:17:23.083\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"pypdf is a free and open-source pure-python PDF library. Prior to 6.15.0, an attacker can craft a PDF that causes long runtimes when the pypdf/_utils.py function read_until_whitespace reads a stream containing a long run of bytes without whitespace. The function repeatedly performs immutable bytes concatenation in a one-byte loop, causing quadratic processing cost for the long non-whitespace input. This issue is fixed in version 6.15.0.\"}],\"affected\":[{\"source\":\"security-advisories@github.com\",\"affectedData\":[{\"vendor\":\"py-pdf\",\"product\":\"pypdf\",\"versions\":[{\"version\":\"\u003c 6.15.0\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV40\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"4.0\",\"vectorString\":\"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/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\",\"baseScore\":6.9,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"attackRequirements\":\"NONE\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"vulnConfidentialityImpact\":\"NONE\",\"vulnIntegrityImpact\":\"NONE\",\"vulnAvailabilityImpact\":\"LOW\",\"subConfidentialityImpact\":\"NONE\",\"subIntegrityImpact\":\"NONE\",\"subAvailabilityImpact\":\"NONE\",\"exploitMaturity\":\"NOT_DEFINED\",\"confidentialityRequirement\":\"NOT_DEFINED\",\"integrityRequirement\":\"NOT_DEFINED\",\"availabilityRequirement\":\"NOT_DEFINED\",\"modifiedAttackVector\":\"NOT_DEFINED\",\"modifiedAttackComplexity\":\"NOT_DEFINED\",\"modifiedAttackRequirements\":\"NOT_DEFINED\",\"modifiedPrivilegesRequired\":\"NOT_DEFINED\",\"modifiedUserInteraction\":\"NOT_DEFINED\",\"modifiedVulnConfidentialityImpact\":\"NOT_DEFINED\",\"modifiedVulnIntegrityImpact\":\"NOT_DEFINED\",\"modifiedVulnAvailabilityImpact\":\"NOT_DEFINED\",\"modifiedSubConfidentialityImpact\":\"NOT_DEFINED\",\"modifiedSubIntegrityImpact\":\"NOT_DEFINED\",\"modifiedSubAvailabilityImpact\":\"NOT_DEFINED\",\"Safety\":\"NOT_DEFINED\",\"Automatable\":\"NOT_DEFINED\",\"Recovery\":\"NOT_DEFINED\",\"valueDensity\":\"NOT_DEFINED\",\"vulnerabilityResponseEffort\":\"NOT_DEFINED\",\"providerUrgency\":\"NOT_DEFINED\"}}]},\"weaknesses\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-407\"}]}],\"references\":[{\"url\":\"https://github.com/py-pdf/pypdf/commit/4959848e057e37c218dccad7465259210923faaa\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/py-pdf/pypdf/pull/3947\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/py-pdf/pypdf/releases/tag/6.15.0\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/py-pdf/pypdf/security/advisories/GHSA-fc8x-2rww-xw9m\",\"source\":\"security-advisories@github.com\"}]}}"
}
}
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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.
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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.
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.
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