CVE-2026-3446 (GCVE-0-2026-3446)
Vulnerability from cvelistv5
Published
2026-04-10 18:17
Modified
2026-04-13 16:07
Severity ?
VLAI Severity ?
EPSS score ?
Summary
When calling base64.b64decode() or related functions the decoding process would stop after encountering the first padded quad regardless of whether there was more information to be processed. This can lead to data being accepted which may be processed differently by other implementations. Use "validate=True" to enable stricter processing of base64 data.
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Python Software Foundation | CPython |
Version: 0 Version: 3.14.0 Version: 3.15.0a1 |
{
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2026-3446",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "no"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-04-13T16:06:04.489473Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-345",
"description": "CWE-345 Insufficient Verification of Data Authenticity",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-04-13T16:07:24.229Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"modules": [
"base64"
],
"product": "CPython",
"repo": "https://github.com/python/cpython",
"vendor": "Python Software Foundation",
"versions": [
{
"lessThan": "3.13.13",
"status": "affected",
"version": "0",
"versionType": "python"
},
{
"lessThan": "3.14.4",
"status": "affected",
"version": "3.14.0",
"versionType": "python"
},
{
"lessThan": "3.15.0a8",
"status": "affected",
"version": "3.15.0a1",
"versionType": "python"
}
]
}
],
"credits": [
{
"lang": "en",
"type": "reporter",
"value": "Serhiy Storchaka"
}
],
"descriptions": [
{
"lang": "en",
"supportingMedia": [
{
"base64": false,
"type": "text/html",
"value": "When calling base64.b64decode() or related functions the decoding process would stop after encountering the first padded quad regardless of whether there was more information to be processed. This can lead to data being accepted which may be processed differently by other implementations. Use \"validate=True\" to enable stricter processing of base64 data."
}
],
"value": "When calling base64.b64decode() or related functions the decoding process would stop after encountering the first padded quad regardless of whether there was more information to be processed. This can lead to data being accepted which may be processed differently by other implementations. Use \"validate=True\" to enable stricter processing of base64 data."
}
],
"metrics": [
{
"cvssV4_0": {
"Automatable": "NOT_DEFINED",
"Recovery": "NOT_DEFINED",
"Safety": "NOT_DEFINED",
"attackComplexity": "HIGH",
"attackRequirements": "PRESENT",
"attackVector": "NETWORK",
"baseScore": 6,
"baseSeverity": "MEDIUM",
"exploitMaturity": "NOT_DEFINED",
"privilegesRequired": "LOW",
"providerUrgency": "NOT_DEFINED",
"subAvailabilityImpact": "NONE",
"subConfidentialityImpact": "NONE",
"subIntegrityImpact": "NONE",
"userInteraction": "NONE",
"valueDensity": "NOT_DEFINED",
"vectorString": "CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N",
"version": "4.0",
"vulnAvailabilityImpact": "NONE",
"vulnConfidentialityImpact": "NONE",
"vulnIntegrityImpact": "HIGH",
"vulnerabilityResponseEffort": "NOT_DEFINED"
},
"format": "CVSS",
"scenarios": [
{
"lang": "en",
"value": "GENERAL"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-04-10T18:26:41.904Z",
"orgId": "28c92f92-d60d-412d-b760-e73465c3df22",
"shortName": "PSF"
},
"references": [
{
"tags": [
"patch"
],
"url": "https://github.com/python/cpython/pull/145267"
},
{
"tags": [
"issue-tracking"
],
"url": "https://github.com/python/cpython/issues/145264"
},
{
"tags": [
"vendor-advisory"
],
"url": "https://mail.python.org/archives/list/security-announce@python.org/thread/F5ZT5ICGJ6CKXVUJ34YBVY7WOZ5SHG53/"
},
{
"tags": [
"patch"
],
"url": "https://github.com/python/cpython/commit/1f9958f909c1b41a4ffc0b613ef8ec8fa5e7c474"
},
{
"tags": [
"patch"
],
"url": "https://github.com/python/cpython/commit/4561f6418a691b3e89aef0901f53fe0dfb7f7c0e"
},
{
"tags": [
"patch"
],
"url": "https://github.com/python/cpython/commit/e31c55121620189a0d1a07b689762d8ca9c1b7fa"
}
],
"source": {
"discovery": "UNKNOWN"
},
"title": "Base64 decoding stops at first padded quad by default",
"x_generator": {
"engine": "cvelib 1.8.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "28c92f92-d60d-412d-b760-e73465c3df22",
"assignerShortName": "PSF",
"cveId": "CVE-2026-3446",
"datePublished": "2026-04-10T18:17:35.045Z",
"dateReserved": "2026-03-02T16:15:14.567Z",
"dateUpdated": "2026-04-13T16:07:24.229Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"vulnrichment": {
"containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-3446\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-04-13T16:06:04.489473Z\"}}}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-345\", \"description\": \"CWE-345 Insufficient Verification of Data Authenticity\"}]}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-04-13T16:07:10.721Z\"}}], \"cna\": {\"title\": \"Base64 decoding stops at first padded quad by default\", \"source\": {\"discovery\": \"UNKNOWN\"}, \"credits\": [{\"lang\": \"en\", \"type\": \"reporter\", \"value\": \"Serhiy Storchaka\"}], \"metrics\": [{\"format\": \"CVSS\", \"cvssV4_0\": {\"Safety\": \"NOT_DEFINED\", \"version\": \"4.0\", \"Recovery\": \"NOT_DEFINED\", \"baseScore\": 6, \"Automatable\": \"NOT_DEFINED\", \"attackVector\": \"NETWORK\", \"baseSeverity\": \"MEDIUM\", \"valueDensity\": \"NOT_DEFINED\", \"vectorString\": \"CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N\", \"exploitMaturity\": \"NOT_DEFINED\", \"providerUrgency\": \"NOT_DEFINED\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"HIGH\", \"attackRequirements\": \"PRESENT\", \"privilegesRequired\": \"LOW\", \"subIntegrityImpact\": \"NONE\", \"vulnIntegrityImpact\": \"HIGH\", \"subAvailabilityImpact\": \"NONE\", \"vulnAvailabilityImpact\": \"NONE\", \"subConfidentialityImpact\": \"NONE\", \"vulnConfidentialityImpact\": \"NONE\", \"vulnerabilityResponseEffort\": \"NOT_DEFINED\"}, \"scenarios\": [{\"lang\": \"en\", \"value\": \"GENERAL\"}]}], \"affected\": [{\"repo\": \"https://github.com/python/cpython\", \"vendor\": \"Python Software Foundation\", \"modules\": [\"base64\"], \"product\": \"CPython\", \"versions\": [{\"status\": \"affected\", \"version\": \"0\", \"lessThan\": \"3.13.13\", \"versionType\": \"python\"}, {\"status\": \"affected\", \"version\": \"3.14.0\", \"lessThan\": \"3.14.4\", \"versionType\": \"python\"}, {\"status\": \"affected\", \"version\": \"3.15.0a1\", \"lessThan\": \"3.15.0a8\", \"versionType\": \"python\"}], \"defaultStatus\": \"unaffected\"}], \"references\": [{\"url\": \"https://github.com/python/cpython/pull/145267\", \"tags\": [\"patch\"]}, {\"url\": \"https://github.com/python/cpython/issues/145264\", \"tags\": [\"issue-tracking\"]}, {\"url\": \"https://mail.python.org/archives/list/security-announce@python.org/thread/F5ZT5ICGJ6CKXVUJ34YBVY7WOZ5SHG53/\", \"tags\": [\"vendor-advisory\"]}, {\"url\": \"https://github.com/python/cpython/commit/1f9958f909c1b41a4ffc0b613ef8ec8fa5e7c474\", \"tags\": [\"patch\"]}, {\"url\": \"https://github.com/python/cpython/commit/4561f6418a691b3e89aef0901f53fe0dfb7f7c0e\", \"tags\": [\"patch\"]}, {\"url\": \"https://github.com/python/cpython/commit/e31c55121620189a0d1a07b689762d8ca9c1b7fa\", \"tags\": [\"patch\"]}], \"x_generator\": {\"engine\": \"cvelib 1.8.0\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"When calling base64.b64decode() or related functions the decoding process would stop after encountering the first padded quad regardless of whether there was more information to be processed. This can lead to data being accepted which may be processed differently by other implementations. Use \\\"validate=True\\\" to enable stricter processing of base64 data.\", \"supportingMedia\": [{\"type\": \"text/html\", \"value\": \"When calling base64.b64decode() or related functions the decoding process would stop after encountering the first padded quad regardless of whether there was more information to be processed. This can lead to data being accepted which may be processed differently by other implementations. Use \\\"validate=True\\\" to enable stricter processing of base64 data.\", \"base64\": false}]}], \"providerMetadata\": {\"orgId\": \"28c92f92-d60d-412d-b760-e73465c3df22\", \"shortName\": \"PSF\", \"dateUpdated\": \"2026-04-10T18:26:41.904Z\"}}}",
"cveMetadata": "{\"cveId\": \"CVE-2026-3446\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-04-13T16:07:24.229Z\", \"dateReserved\": \"2026-03-02T16:15:14.567Z\", \"assignerOrgId\": \"28c92f92-d60d-412d-b760-e73465c3df22\", \"datePublished\": \"2026-04-10T18:17:35.045Z\", \"assignerShortName\": \"PSF\"}",
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
}
}
Loading…
Loading…
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
Loading…
Loading…