pyjwt — security advisory
PyJWT is a JSON Web Token implementation in Python. From 2.8.0 to 2.12.1, when verifying detached JWS tokens using the unencoded-payload option ("b64": false, RFC 7797), PyJWT performs Base64URL decoding of the compact-serialization payload segment before enforcing the detached-payload rules. For b64=false, PyJWT later discards that decoded payload and replaces it with the caller-provided detached_payload. In practice, this turns the middle segment into an attacker-controlled “work amplifier”: a remote client can supply an arbitrarily large Base64URL payload segment that forces CPU work + memory allocations even if the signature is invalid. This creates an unauthenticated DoS vector against any endpoint that verifies detached JWS using PyJWT. This vulnerability is fixed in 2.13.0.
- Products
- pyjwt
- Affected versions
- 2.10.1-1, 2.10.1-2, 2.10.1-2+deb13u1, 2.10.1-3, 2.10.1-4, 2.11.0-2, 2.12.1-1, 2.13.0-1, 2.14.0-1, 2.15.0-1, 2.15.1-1, 2.6.0-1, 2.6.0-1+deb12u1, 2.7.0-1
- Fixed versions
- 2.13.0-1
- CVEs
- CVE-2026-48525
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 12:16 UTC · Revision 2
Source evidence
PyJWT is a JSON Web Token implementation in Python. From 2.8.0 to 2.12.1, when verifying detached JWS tokens using the unencoded-payload option ("b64": false, RFC 7797), PyJWT performs Base64URL decoding of the compact-serialization payload segment before enforcing the detached-payload rules. For b64=false, PyJWT later discards that decoded payload and replaces it with the caller-provided detached_payload. In practice, this turns the middle segment into an attacker-controlled “work amplifier”: a remote client can supply an arbitrarily large Base64URL payload segment that forces CPU work + memory allocations even if the signature is invalid. This creates an unauthenticated DoS vector against any endpoint that verifies detached JWS using PyJWT. This vulnerability is fixed in 2.13.0.
osv:DEBIAN-CVE-2026-48525
pyjwt
Fixed versions: Not specified
pyjwt
Fixed versions: Not specified
pyjwt
Fixed versions: 2.13.0-1
Complete source record
{
"id": "079890c6399d018ad0b598b1cf3a78e633a15b5b7bdc0cc68a21f9d1c2d6e4b4",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-48525",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2026-48525",
"summary": "PyJWT is a JSON Web Token implementation in Python. From 2.8.0 to 2.12.1, when verifying detached JWS tokens using the unencoded-payload option (\"b64\": false, RFC 7797), PyJWT performs Base64URL decoding of the compact-serialization payload segment before enforcing the detached-payload rules. For b64=false, PyJWT later discards that decoded payload and replaces it with the caller-provided detached_payload. In practice, this turns the middle segment into an attacker-controlled “work amplifier”: a remote client can supply an arbitrarily large Base64URL payload segment that forces CPU work + memory allocations even if the signature is invalid. This creates an unauthenticated DoS vector against any endpoint that verifies detached JWS using PyJWT. This vulnerability is fixed in 2.13.0.",
"evidence": "osv:DEBIAN-CVE-2026-48525",
"products": [
{
"name": {
"value": "pyjwt",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "2.10.1-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.10.1-2",
"evidence": "/affected/0/versions"
},
{
"value": "2.10.1-3",
"evidence": "/affected/0/versions"
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{
"value": "2.10.1-4",
"evidence": "/affected/0/versions"
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{
"value": "2.11.0-2",
"evidence": "/affected/0/versions"
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{
"value": "2.12.1-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.13.0-1",
"evidence": "/affected/0/versions"
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{
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"evidence": "/affected/0/versions"
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{
"value": "2.15.0-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.15.1-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.6.0-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.6.0-1+deb12u1",
"evidence": "/affected/0/versions"
},
{
"value": "2.7.0-1",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
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"evidence": "/affected/1/package/name"
},
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"affected_versions": [
{
"value": "2.10.1-2",
"evidence": "/affected/1/versions"
},
{
"value": "2.10.1-2+deb13u1",
"evidence": "/affected/1/versions"
},
{
"value": "2.10.1-3",
"evidence": "/affected/1/versions"
},
{
"value": "2.10.1-4",
"evidence": "/affected/1/versions"
},
{
"value": "2.11.0-2",
"evidence": "/affected/1/versions"
},
{
"value": "2.12.1-1",
"evidence": "/affected/1/versions"
},
{
"value": "2.13.0-1",
"evidence": "/affected/1/versions"
},
{
"value": "2.14.0-1",
"evidence": "/affected/1/versions"
},
{
"value": "2.15.0-1",
"evidence": "/affected/1/versions"
},
{
"value": "2.15.1-1",
"evidence": "/affected/1/versions"
}
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},
{
"name": {
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"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [
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"evidence": "/affected/2/ranges"
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],
"affected_versions": [
{
"value": "2.10.1-2",
"evidence": "/affected/2/versions"
},
{
"value": "2.10.1-3",
"evidence": "/affected/2/versions"
},
{
"value": "2.10.1-4",
"evidence": "/affected/2/versions"
},
{
"value": "2.11.0-2",
"evidence": "/affected/2/versions"
},
{
"value": "2.12.1-1",
"evidence": "/affected/2/versions"
}
]
}
],
"severity": "medium",
"structured": {
"id": "DEBIAN-CVE-2026-48525",
"aliases": [
"DEBIAN-CVE-2026-48525"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
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],
"package": {
"name": "pyjwt",
"purl": "pkg:deb/debian/pyjwt?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"versions": [
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"2.10.1-2",
"2.10.1-3",
"2.10.1-4",
"2.11.0-2",
"2.12.1-1",
"2.13.0-1",
"2.14.0-1",
"2.15.0-1",
"2.15.1-1",
"2.6.0-1",
"2.6.0-1+deb12u1",
"2.7.0-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-48525.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
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"events": [
{
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}
]
}
],
"package": {
"name": "pyjwt",
"purl": "pkg:deb/debian/pyjwt?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
"2.10.1-2",
"2.10.1-2+deb13u1",
"2.10.1-3",
"2.10.1-4",
"2.11.0-2",
"2.12.1-1",
"2.13.0-1",
"2.14.0-1",
"2.15.0-1",
"2.15.1-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-48525.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "2.13.0-1"
}
]
}
],
"package": {
"name": "pyjwt",
"purl": "pkg:deb/debian/pyjwt?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"versions": [
"2.10.1-2",
"2.10.1-3",
"2.10.1-4",
"2.11.0-2",
"2.12.1-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-48525.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-26T11:47:24.585177344Z",
"provider": "osv",
"upstream": [
"CVE-2026-48525"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2026-48525"
]
},
"related_cves": [
{
"value": "CVE-2026-48525",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 450757,
"published_at": "2026-05-28T16:16:29.533+00:00"
}