Fix CVE(s): CVE-2026-66046, CVE-2026-93990
* SECURITY UPDATE: denial of service through quadratic runtime in the default-attribute lookup performed by storeAtts() - debian/patches/CVE-2026-66046.patch: resolve the CDATA-ness of a specified attribute through the per-element defaultAttForName hash table instead of a linear scan of defaultAtts, and fold in the upstream follow-up that makes dtdCopy create entries of the same size so storeAtts does not read .attIndex out of bounds (libexpat PR #1321, PR #1331). - CVE-2026-66046 * SECURITY UPDATE: malformed UTF-16 accepted because a high surrogate was not required to be followed by a low surrogate - debian/patches/CVE-2026-93990.patch: reject a 4-byte UTF-16 sequence whose second code unit is not a low surrogate, in both the little2_ and big2_ tokenizers (libexpat PR #1282). - CVE-2026-93990
- Products
- expat, libexpat1, libexpat1-dev
- Affected versions
- Not specified
- Fixed versions
- 2.2.5-3ubuntu0.9+tuxcare.els12
- CVEs
- CVE-2026-66046, CVE-2026-93990
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 11:42 UTC · Revision 1
Source evidence
Fix CVE(s): CVE-2026-66046, CVE-2026-93990
core-osv · Original sourcePublished 24 Sept 2026, 23:00 UTC
* SECURITY UPDATE: denial of service through quadratic runtime in the default-attribute lookup performed by storeAtts() - debian/patches/CVE-2026-66046.patch: resolve the CDATA-ness of a specified attribute through the per-element defaultAttForName hash table instead of a linear scan of defaultAtts, and fold in the upstream follow-up that makes dtdCopy create entries of the same size so storeAtts does not read .attIndex out of bounds (libexpat PR #1321, PR #1331). - CVE-2026-66046 * SECURITY UPDATE: malformed UTF-16 accepted because a high surrogate was not required to be followed by a low surrogate - debian/patches/CVE-2026-93990.patch: reject a 4-byte UTF-16 sequence whose second code unit is not a low surrogate, in both the little2_ and big2_ tokenizers (libexpat PR #1282). - CVE-2026-93990
osv:CLSA-2026-1790290820
expat
Fixed versions: 2.2.5-3ubuntu0.9+tuxcare.els12
libexpat1
Fixed versions: 2.2.5-3ubuntu0.9+tuxcare.els12
libexpat1-dev
Fixed versions: 2.2.5-3ubuntu0.9+tuxcare.els12
Complete source record
{
"id": "c8597fa9a3dd9d756bc3bc27a2f54827576573bf56d71f1b9068fc40769fae4b",
"url": "https://osv.dev/vulnerability/CLSA-2026-1790290820",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "Fix CVE(s): CVE-2026-66046, CVE-2026-93990",
"summary": "* SECURITY UPDATE: denial of service through quadratic runtime in the default-attribute lookup performed by storeAtts() - debian/patches/CVE-2026-66046.patch: resolve the CDATA-ness of a specified attribute through the per-element defaultAttForName hash table instead of a linear scan of defaultAtts, and fold in the upstream follow-up that makes dtdCopy create entries of the same size so storeAtts does not read .attIndex out of bounds (libexpat PR #1321, PR #1331). - CVE-2026-66046 * SECURITY UPDATE: malformed UTF-16 accepted because a high surrogate was not required to be followed by a low surrogate - debian/patches/CVE-2026-93990.patch: reject a 4-byte UTF-16 sequence whose second code unit is not a low surrogate, in both the little2_ and big2_ tokenizers (libexpat PR #1282). - CVE-2026-93990",
"evidence": "osv:CLSA-2026-1790290820",
"products": [
{
"name": {
"value": "expat",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "2.2.5-3ubuntu0.9+tuxcare.els12",
"evidence": "/affected/0/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "libexpat1",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "2.2.5-3ubuntu0.9+tuxcare.els12",
"evidence": "/affected/1/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "libexpat1-dev",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "2.2.5-3ubuntu0.9+tuxcare.els12",
"evidence": "/affected/2/ranges"
}
],
"affected_versions": []
}
],
"severity": "unknown",
"structured": {
"id": "CLSA-2026-1790290820",
"aliases": [
"CLSA-2026-1790290820"
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "2.2.5-3ubuntu0.9+tuxcare.els12"
}
]
}
],
"package": {
"name": "expat",
"purl": "pkg:deb/tuxcare/expat?distro=ubuntu-18.04",
"ecosystem": "TuxCare:Ubuntu:18.04"
},
"database_specific": {
"source": "https://github.com/cloudlinux/tuxcare-osv/tree/main/data/els_os/ubuntu18.04els/CLSA-2026-1790290820.json"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "2.2.5-3ubuntu0.9+tuxcare.els12"
}
]
}
],
"package": {
"name": "libexpat1",
"purl": "pkg:deb/tuxcare/libexpat1?distro=ubuntu-18.04",
"ecosystem": "TuxCare:Ubuntu:18.04"
},
"database_specific": {
"source": "https://github.com/cloudlinux/tuxcare-osv/tree/main/data/els_os/ubuntu18.04els/CLSA-2026-1790290820.json"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "2.2.5-3ubuntu0.9+tuxcare.els12"
}
]
}
],
"package": {
"name": "libexpat1-dev",
"purl": "pkg:deb/tuxcare/libexpat1-dev?distro=ubuntu-18.04",
"ecosystem": "TuxCare:Ubuntu:18.04"
},
"database_specific": {
"source": "https://github.com/cloudlinux/tuxcare-osv/tree/main/data/els_os/ubuntu18.04els/CLSA-2026-1790290820.json"
}
}
],
"modified": "2026-10-26T09:32:04.279735540Z",
"provider": "osv",
"upstream": [
"CVE-2026-66046",
"CVE-2026-93990"
],
"references": [
"https://errata.tuxcare.com/els_os/ubuntu18.04els/CLSA-2026-1790290820.html",
"https://nvd.nist.gov/vuln/detail/CVE-2026-66046",
"https://nvd.nist.gov/vuln/detail/CVE-2026-93990"
]
},
"related_cves": [
{
"value": "CVE-2026-66046",
"evidence": "/upstream"
},
{
"value": "CVE-2026-93990",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": null
},
"source_id": "core-osv",
"document_id": 449594,
"published_at": "2026-09-24T23:00:32+00:00"
}