curl — security advisory
curl 7.63.0 to and including 7.75.0 includes vulnerability that allows a malicious HTTPS proxy to MITM a connection due to bad handling of TLS 1.3 session tickets. When using a HTTPS proxy and TLS 1.3, libcurl can confuse session tickets arriving from the HTTPS proxy but work as if they arrived from the remote server and then wrongly "short-cut" the host handshake. When confusing the tickets, a HTTPS proxy can trick libcurl to use the wrong session ticket resume for the host and thereby circumvent the server TLS certificate check and make a MITM attack to be possible to perform unnoticed. Note that such a malicious HTTPS proxy needs to provide a certificate that curl will accept for the MITMed server for an attack to work - unless curl has been told to ignore the server certificate check.
- Products
- curl
- Affected versions
- Not specified
- Fixed versions
- 7.74.0-1.2
- CVEs
- CVE-2021-22890
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 30 Oct 2026, 16:53 UTC · Revision 1
Source evidence
curl 7.63.0 to and including 7.75.0 includes vulnerability that allows a malicious HTTPS proxy to MITM a connection due to bad handling of TLS 1.3 session tickets. When using a HTTPS proxy and TLS 1.3, libcurl can confuse session tickets arriving from the HTTPS proxy but work as if they arrived from the remote server and then wrongly "short-cut" the host handshake. When confusing the tickets, a HTTPS proxy can trick libcurl to use the wrong session ticket resume for the host and thereby circumvent the server TLS certificate check and make a MITM attack to be possible to perform unnoticed. Note that such a malicious HTTPS proxy needs to provide a certificate that curl will accept for the MITMed server for an attack to work - unless curl has been told to ignore the server certificate check.
osv:DEBIAN-CVE-2021-22890
curl
Fixed versions: 7.74.0-1.2
curl
Fixed versions: 7.74.0-1.2
curl
Fixed versions: 7.74.0-1.2
Complete source record
{
"id": "1069495beb3679c4038a3f31cc3f759a4cd38d954831f07df42bd65134a36e3c",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2021-22890",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2021-22890",
"summary": "curl 7.63.0 to and including 7.75.0 includes vulnerability that allows a malicious HTTPS proxy to MITM a connection due to bad handling of TLS 1.3 session tickets. When using a HTTPS proxy and TLS 1.3, libcurl can confuse session tickets arriving from the HTTPS proxy but work as if they arrived from the remote server and then wrongly \"short-cut\" the host handshake. When confusing the tickets, a HTTPS proxy can trick libcurl to use the wrong session ticket resume for the host and thereby circumvent the server TLS certificate check and make a MITM attack to be possible to perform unnoticed. Note that such a malicious HTTPS proxy needs to provide a certificate that curl will accept for the MITMed server for an attack to work - unless curl has been told to ignore the server certificate check.",
"evidence": "osv:DEBIAN-CVE-2021-22890",
"products": [
{
"name": {
"value": "curl",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "7.74.0-1.2",
"evidence": "/affected/0/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "curl",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "7.74.0-1.2",
"evidence": "/affected/1/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "curl",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "7.74.0-1.2",
"evidence": "/affected/2/ranges"
}
],
"affected_versions": []
}
],
"severity": "low",
"structured": {
"id": "DEBIAN-CVE-2021-22890",
"aliases": [
"DEBIAN-CVE-2021-22890"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "7.74.0-1.2"
}
]
}
],
"package": {
"name": "curl",
"purl": "pkg:deb/debian/curl?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-22890.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "7.74.0-1.2"
}
]
}
],
"package": {
"name": "curl",
"purl": "pkg:deb/debian/curl?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-22890.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "7.74.0-1.2"
}
]
}
],
"package": {
"name": "curl",
"purl": "pkg:deb/debian/curl?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-22890.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-15T09:47:43.150351322Z",
"provider": "osv",
"upstream": [
"CVE-2021-22890"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2021-22890"
]
},
"related_cves": [
{
"value": "CVE-2021-22890",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 328495,
"published_at": "2021-04-01T18:15:12.917+00:00"
}