HighFix available
curl — security advisory
A `Set-Cookie:` header using tab (horizontal tab, ASCII code 9) instead of space (ascii code 32) immediately before the `Secure` attribute causes curl to store the cookie without its Secure flag. The cookie might then wrongfully be sent over plaintext HTTP on subsequent requests to the same host.
- Products
- curl
- Affected versions
- 8.14.1-2ubuntu1, 8.17.0-1ubuntu1, 8.18.0-1ubuntu1, 8.18.0-1ubuntu2, 8.18.0-1ubuntu2.1, 8.18.0-1ubuntu2.2, 8.18.0-1ubuntu2.3, 8.18.0-1ubuntu2.4, 8.18.0-1ubuntu2.5, 8.20.0-2ubuntu1, 8.20.0-2ubuntu10, 8.20.0-2ubuntu3
- Fixed versions
- 8.18.0-1ubuntu2.7, 8.20.0-2ubuntu11
- CVEs
- CVE-2026-80255
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 03:20 UTC · Revision 1
Source evidence
A `Set-Cookie:` header using tab (horizontal tab, ASCII code 9) instead of space (ascii code 32) immediately before the `Secure` attribute causes curl to store the cookie without its Secure flag. The cookie might then wrongfully be sent over plaintext HTTP on subsequent requests to the same host.
osv:UBUNTU-CVE-2026-80255
curl
Fixed versions: 8.20.0-2ubuntu11
curl
Fixed versions: 8.18.0-1ubuntu2.7
Complete source record
{
"id": "28b9f8cf75a37a28d24956a30e53c623c3f725b491c24636afa00c3f9a5e8037",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-80255",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2026-80255",
"summary": "A `Set-Cookie:` header using tab (horizontal tab, ASCII code 9) instead of space (ascii code 32) immediately before the `Secure` attribute causes curl to store the cookie without its Secure flag. The cookie might then wrongfully be sent over plaintext HTTP on subsequent requests to the same host.",
"evidence": "osv:UBUNTU-CVE-2026-80255",
"products": [
{
"name": {
"value": "curl",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "8.20.0-2ubuntu11",
"evidence": "/affected/0/ranges"
}
],
"affected_versions": [
{
"value": "8.18.0-1ubuntu2",
"evidence": "/affected/0/versions"
},
{
"value": "8.20.0-2ubuntu1",
"evidence": "/affected/0/versions"
},
{
"value": "8.20.0-2ubuntu3",
"evidence": "/affected/0/versions"
},
{
"value": "8.20.0-2ubuntu10",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
"value": "curl",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "8.18.0-1ubuntu2.7",
"evidence": "/affected/1/ranges"
}
],
"affected_versions": [
{
"value": "8.14.1-2ubuntu1",
"evidence": "/affected/1/versions"
},
{
"value": "8.17.0-1ubuntu1",
"evidence": "/affected/1/versions"
},
{
"value": "8.18.0-1ubuntu1",
"evidence": "/affected/1/versions"
},
{
"value": "8.18.0-1ubuntu2",
"evidence": "/affected/1/versions"
},
{
"value": "8.18.0-1ubuntu2.1",
"evidence": "/affected/1/versions"
},
{
"value": "8.18.0-1ubuntu2.2",
"evidence": "/affected/1/versions"
},
{
"value": "8.18.0-1ubuntu2.3",
"evidence": "/affected/1/versions"
},
{
"value": "8.18.0-1ubuntu2.4",
"evidence": "/affected/1/versions"
},
{
"value": "8.18.0-1ubuntu2.5",
"evidence": "/affected/1/versions"
}
]
}
],
"severity": "high",
"structured": {
"id": "UBUNTU-CVE-2026-80255",
"aliases": [
"UBUNTU-CVE-2026-80255"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N"
},
{
"type": "Ubuntu",
"score": "medium"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "8.20.0-2ubuntu11"
}
]
}
],
"package": {
"name": "curl",
"purl": "pkg:deb/ubuntu/curl?arch=source&distro=stonking",
"ecosystem": "Ubuntu:26.10"
},
"versions": [
"8.18.0-1ubuntu2",
"8.20.0-2ubuntu1",
"8.20.0-2ubuntu3",
"8.20.0-2ubuntu10"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-80255.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "curl",
"binary_version": "8.20.0-2ubuntu11"
},
{
"binary_name": "libcurl3t64-gnutls",
"binary_version": "8.20.0-2ubuntu11"
},
{
"binary_name": "libcurl4t64",
"binary_version": "8.20.0-2ubuntu11"
}
],
"availability": "No subscription required"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "8.18.0-1ubuntu2.7"
}
]
}
],
"package": {
"name": "curl",
"purl": "pkg:deb/ubuntu/curl?arch=source&distro=resolute",
"ecosystem": "Ubuntu:26.04:LTS"
},
"versions": [
"8.14.1-2ubuntu1",
"8.17.0-1ubuntu1",
"8.18.0-1ubuntu1",
"8.18.0-1ubuntu2",
"8.18.0-1ubuntu2.1",
"8.18.0-1ubuntu2.2",
"8.18.0-1ubuntu2.3",
"8.18.0-1ubuntu2.4",
"8.18.0-1ubuntu2.5"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-80255.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "curl",
"binary_version": "8.18.0-1ubuntu2.7"
},
{
"binary_name": "libcurl3t64-gnutls",
"binary_version": "8.18.0-1ubuntu2.7"
},
{
"binary_name": "libcurl4t64",
"binary_version": "8.18.0-1ubuntu2.7"
}
],
"availability": "No subscription required"
}
}
],
"modified": "2026-10-17T13:01:10.288597814Z",
"provider": "osv",
"upstream": [
"CVE-2026-80255"
],
"references": [
"https://ubuntu.com/security/CVE-2026-80255",
"https://www.cve.org/CVERecord?id=CVE-2026-80255",
"https://curl.se/docs/CVE-2026-80255.html",
"https://github.com/curl/curl/commit/4f6aa41a0145e930e76677",
"https://ubuntu.com/security/notices/USN-8820-1"
]
},
"related_cves": [
{
"value": "CVE-2026-80255",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 361118,
"published_at": "2026-09-06T18:17:00+00:00"
}