Medium
bird, bird2 and 1 more products — security advisory
CZ.NIC BIRD Internet Routing Daemon through 2.19.0 contains a stack-based buffer overflow in the BGP AS_PATH mask matching implementation in nest/a-path.c. The as_path_match() function uses a fixed-size stack array of 2048 + 1 pm_pos entries, while parse_path() expands AS_PATH segments from a received BGP UPDATE without enforcing a corresponding capacity limit. When RFC 8654 BGP Extended Messages are enabled and a BIRD filter evaluates an AS path mask expression such as "bgp_path ~ [= ... =]", an established BGP peer can send a long AS_PATH containing more than 2048 expanded ASNs. This causes parse_path()/as_path_match() to write beyond the fixed stack buffer, resulting in a crash of the daemon. NOTE: reportedly, the Supplier's position is that a fix is not being prioritized because all network operators should already be rejecting routes with unusually long attributes.
- Products
- bird, bird2, bird3
- Affected versions
- 1.5.0-4, 1.5.0-4build1, 1.6.3-3, 1.6.7-1, 1.6.8-1, 1.6.8-2.1, 1.6.8-2.1build1, 1.6.8-2.1build2, 2.0.12-7, 2.0.5-1, 2.0.7-2, 2.0.7-4.1, 2.0.8-2, 2.14-1, 2.14-1build1, 2.14-1build2, 2.16.1-1, 2.17-1, 2.17.1-1, 2.17.2-1, 2.17.3-1, 2.17.3-2, 2.18-1, 2.18.1-1, 2.19.0-1, 2.19.1-1, 2.19.2-1, 3.1.0-1, 3.1.4-1, 3.1.5-1, 3.1.5-2, 3.2.0-1, 3.2.1-1, 3.3.0-1, 3.3.1-1, 3.3.2-1
- Fixed versions
- Not specified
- CVEs
- CVE-2026-49943
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 02:26 UTC · Revision 1
Source evidence
CZ.NIC BIRD Internet Routing Daemon through 2.19.0 contains a stack-based buffer overflow in the BGP AS_PATH mask matching implementation in nest/a-path.c. The as_path_match() function uses a fixed-size stack array of 2048 + 1 pm_pos entries, while parse_path() expands AS_PATH segments from a received BGP UPDATE without enforcing a corresponding capacity limit. When RFC 8654 BGP Extended Messages are enabled and a BIRD filter evaluates an AS path mask expression such as "bgp_path ~ [= ... =]", an established BGP peer can send a long AS_PATH containing more than 2048 expanded ASNs. This causes parse_path()/as_path_match() to write beyond the fixed stack buffer, resulting in a crash of the daemon. NOTE: reportedly, the Supplier's position is that a fix is not being prioritized because all network operators should already be rejecting routes with unusually long attributes.
osv:UBUNTU-CVE-2026-49943
bird
Fixed versions: Not specified
bird
Fixed versions: Not specified
bird
Fixed versions: Not specified
bird2
Fixed versions: Not specified
bird
Fixed versions: Not specified
bird2
Fixed versions: Not specified
bird
Fixed versions: Not specified
bird2
Fixed versions: Not specified
bird2
Fixed versions: Not specified
bird3
Fixed versions: Not specified
bird2
Fixed versions: Not specified
bird3
Fixed versions: Not specified
bird2
Fixed versions: Not specified
bird3
Fixed versions: Not specified
Complete source record
{
"id": "4ba875a116119bc87fcf71f1f227a616818ea82db445361b205b712c4dcc92b5",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-49943",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2026-49943",
"summary": "CZ.NIC BIRD Internet Routing Daemon through 2.19.0 contains a stack-based buffer overflow in the BGP AS_PATH mask matching implementation in nest/a-path.c. The as_path_match() function uses a fixed-size stack array of 2048 + 1 pm_pos entries, while parse_path() expands AS_PATH segments from a received BGP UPDATE without enforcing a corresponding capacity limit. When RFC 8654 BGP Extended Messages are enabled and a BIRD filter evaluates an AS path mask expression such as \"bgp_path ~ [= ... =]\", an established BGP peer can send a long AS_PATH containing more than 2048 expanded ASNs. This causes parse_path()/as_path_match() to write beyond the fixed stack buffer, resulting in a crash of the daemon. NOTE: reportedly, the Supplier's position is that a fix is not being prioritized because all network operators should already be rejecting routes with unusually long attributes.",
"evidence": "osv:UBUNTU-CVE-2026-49943",
"products": [
{
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},
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{
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"evidence": "/affected/0/versions"
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{
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"evidence": "/affected/0/versions"
}
]
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{
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{
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{
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}
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{
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{
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{
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]
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{
"name": {
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"evidence": "/affected/8/package/name"
},
"prerequisites": [],
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"affected_versions": [
{
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"evidence": "/affected/8/versions"
},
{
"value": "2.17-1",
"evidence": "/affected/8/versions"
},
{
"value": "2.17.1-1",
"evidence": "/affected/8/versions"
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]
},
{
"name": {
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"evidence": "/affected/9/package/name"
},
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{
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{
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{
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{
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{
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},
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{
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"evidence": "/affected/11/versions"
},
{
"value": "3.2.1-1",
"evidence": "/affected/11/versions"
},
{
"value": "3.3.0-1",
"evidence": "/affected/11/versions"
},
{
"value": "3.3.1-1",
"evidence": "/affected/11/versions"
},
{
"value": "3.3.2-1",
"evidence": "/affected/11/versions"
}
]
},
{
"name": {
"value": "bird2",
"evidence": "/affected/12/package/name"
},
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"affected_versions": [
{
"value": "2.17.1-1",
"evidence": "/affected/12/versions"
},
{
"value": "2.17.2-1",
"evidence": "/affected/12/versions"
},
{
"value": "2.17.3-1",
"evidence": "/affected/12/versions"
},
{
"value": "2.17.3-2",
"evidence": "/affected/12/versions"
},
{
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"evidence": "/affected/12/versions"
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]
},
{
"name": {
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"evidence": "/affected/13/package/name"
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{
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"evidence": "/affected/13/versions"
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{
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],
"severity": "medium",
"structured": {
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"aliases": [
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],
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"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:N/I:N/A:H"
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},
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},
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},
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},
"versions": [
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],
"database_specific": {
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},
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},
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},
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"2.17.3-2",
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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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"3.1.4-1",
"3.1.5-1",
"3.1.5-2",
"3.2.0-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-49943.json"
},
"ecosystem_specific": {
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{
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"binary_version": "3.2.0-1"
}
]
}
}
],
"modified": "2026-10-17T12:58:32.647579395Z",
"provider": "osv",
"upstream": [
"CVE-2026-49943"
],
"references": [
"https://ubuntu.com/security/CVE-2026-49943",
"https://www.cve.org/CVERecord?id=CVE-2026-49943",
"https://www.openwall.com/lists/oss-security/2026/06/02/2"
]
},
"related_cves": [
{
"value": "CVE-2026-49943",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 358727,
"published_at": "2026-06-02T17:16:00+00:00"
}