CriticalFix available
libauthen-sasl-perl — security advisory
Authen::SASL::Perl::DIGEST_MD5 versions before 2.2100 for Perl accept replayed authentication responses via unverified nonce in server_step. server_start generates a fresh nonce and sends it in the challenge, and nothing later compares that value against the nonce the client returns. server_step derives the expected digest from the client's own parameters, so a response verifies whenever its digest matches the nonce it carries. The count table it also checks is keyed on the client-supplied nonce and starts empty in each new server object, so a captured first response, carrying `nc=00000001`, passes that too. RFC 2831 defines the nonce in the response as the value the server sent in the preceding challenge. An attacker who observes one successful `qop=auth` exchange can replay the captured response against a later session for the same service, host, realm and user, and authenticate as that user without knowing the password.
- Products
- libauthen-sasl-perl
- Affected versions
- 2.1500-1, 2.1600-1, 2.1600-1.1, 2.1600-3, 2.1700-1, 2.2000-1
- Fixed versions
- 2.1500-1ubuntu0.1~esm1, 2.1600-1.1ubuntu0.1, 2.1600-1ubuntu0.16.04.1~esm1, 2.1600-1ubuntu0.18.04.1~esm1, 2.1600-1ubuntu0.20.04.1~esm1, 2.1700-1ubuntu0.1, 2.2000-1ubuntu0.1, 2.2000-1ubuntu1
- CVEs
- CVE-2026-86219
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 03:24 UTC · Revision 1
Source evidence
Authen::SASL::Perl::DIGEST_MD5 versions before 2.2100 for Perl accept replayed authentication responses via unverified nonce in server_step. server_start generates a fresh nonce and sends it in the challenge, and nothing later compares that value against the nonce the client returns. server_step derives the expected digest from the client's own parameters, so a response verifies whenever its digest matches the nonce it carries. The count table it also checks is keyed on the client-supplied nonce and starts empty in each new server object, so a captured first response, carrying `nc=00000001`, passes that too. RFC 2831 defines the nonce in the response as the value the server sent in the preceding challenge. An attacker who observes one successful `qop=auth` exchange can replay the captured response against a later session for the same service, host, realm and user, and authenticate as that user without knowing the password.
osv:UBUNTU-CVE-2026-86219
libauthen-sasl-perl
Fixed versions: 2.1500-1ubuntu0.1~esm1
libauthen-sasl-perl
Fixed versions: 2.1600-1ubuntu0.16.04.1~esm1
libauthen-sasl-perl
Fixed versions: 2.1600-1ubuntu0.18.04.1~esm1
libauthen-sasl-perl
Fixed versions: 2.1600-1ubuntu0.20.04.1~esm1
libauthen-sasl-perl
Fixed versions: 2.1600-1.1ubuntu0.1
libauthen-sasl-perl
Fixed versions: 2.1700-1ubuntu0.1
libauthen-sasl-perl
Fixed versions: 2.2000-1ubuntu1
libauthen-sasl-perl
Fixed versions: 2.2000-1ubuntu0.1
Complete source record
{
"id": "16074c1f425542d55f9204f6183cab3950564c9dd38b3dd7c69346f263e52037",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-86219",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2026-86219",
"summary": "Authen::SASL::Perl::DIGEST_MD5 versions before 2.2100 for Perl accept replayed authentication responses via unverified nonce in server_step. server_start generates a fresh nonce and sends it in the challenge, and nothing later compares that value against the nonce the client returns. server_step derives the expected digest from the client's own parameters, so a response verifies whenever its digest matches the nonce it carries. The count table it also checks is keyed on the client-supplied nonce and starts empty in each new server object, so a captured first response, carrying `nc=00000001`, passes that too. RFC 2831 defines the nonce in the response as the value the server sent in the preceding challenge. An attacker who observes one successful `qop=auth` exchange can replay the captured response against a later session for the same service, host, realm and user, and authenticate as that user without knowing the password.",
"evidence": "osv:UBUNTU-CVE-2026-86219",
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{
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{
"name": {
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"fixed_versions": [
{
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"evidence": "/affected/7/ranges"
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],
"affected_versions": [
{
"value": "2.1700-1",
"evidence": "/affected/7/versions"
},
{
"value": "2.2000-1",
"evidence": "/affected/7/versions"
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],
"severity": "critical",
"structured": {
"id": "UBUNTU-CVE-2026-86219",
"aliases": [
"UBUNTU-CVE-2026-86219"
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"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
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{
"type": "Ubuntu",
"score": "medium"
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"affected": [
{
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{
"type": "ECOSYSTEM",
"events": [
{
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{
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]
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],
"package": {
"name": "libauthen-sasl-perl",
"purl": "pkg:deb/ubuntu/libauthen-sasl-perl?arch=source&distro=esm-infra-legacy%2Ftrusty",
"ecosystem": "Ubuntu:Pro:14.04:LTS"
},
"versions": [
"2.1500-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-86219.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libauthen-sasl-perl",
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}
],
"availability": "Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro"
}
},
{
"ranges": [
{
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{
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{
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}
]
}
],
"package": {
"name": "libauthen-sasl-perl",
"purl": "pkg:deb/ubuntu/libauthen-sasl-perl?arch=source&distro=esm-infra-legacy%2Fxenial",
"ecosystem": "Ubuntu:Pro:16.04:LTS"
},
"versions": [
"2.1600-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-86219.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libauthen-sasl-perl",
"binary_version": "2.1600-1ubuntu0.16.04.1~esm1"
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],
"availability": "Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro"
}
},
{
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{
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],
"package": {
"name": "libauthen-sasl-perl",
"purl": "pkg:deb/ubuntu/libauthen-sasl-perl?arch=source&distro=esm-infra%2Fbionic",
"ecosystem": "Ubuntu:Pro:18.04:LTS"
},
"versions": [
"2.1600-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-86219.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libauthen-sasl-perl",
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],
"availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
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{
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{
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],
"package": {
"name": "libauthen-sasl-perl",
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"ecosystem": "Ubuntu:Pro:20.04:LTS"
},
"versions": [
"2.1600-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-86219.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libauthen-sasl-perl",
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},
{
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{
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],
"package": {
"name": "libauthen-sasl-perl",
"purl": "pkg:deb/ubuntu/libauthen-sasl-perl?arch=source&distro=jammy",
"ecosystem": "Ubuntu:22.04:LTS"
},
"versions": [
"2.1600-1.1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-86219.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libauthen-sasl-perl",
"binary_version": "2.1600-1.1ubuntu0.1"
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"binaries": [
{
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{
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{
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"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-86219.json"
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{
"binary_name": "libauthen-sasl-perl",
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},
{
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{
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"package": {
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"ecosystem": "Ubuntu:26.04:LTS"
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"versions": [
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"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-86219.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libauthen-sasl-perl",
"binary_version": "2.2000-1ubuntu0.1"
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],
"availability": "No subscription required"
}
}
],
"modified": "2026-10-17T13:01:13.516107519Z",
"provider": "osv",
"upstream": [
"CVE-2026-86219"
],
"references": [
"https://ubuntu.com/security/CVE-2026-86219",
"https://www.cve.org/CVERecord?id=CVE-2026-86219",
"https://lists.security.metacpan.org/cve-announce/msg/43326063/",
"https://ubuntu.com/security/notices/USN-8858-1"
]
},
"related_cves": [
{
"value": "CVE-2026-86219",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 361302,
"published_at": "2026-09-06T18:17:00+00:00"
}