Vulnerability-Lookup

GHSA-64C8-8QX9-25R7

Vulnerability from github – Published: 2026-06-02 18:31 – Updated: 2026-06-02 18:31

Details

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.

Severity

6.3 (Medium)


                  
                    CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:N/I:N/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2026-49943"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-121"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-06-02T17:16:37Z",
    "severity": "MODERATE"
  },
  "details": "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\u0027s position is that a fix is not being prioritized because all network operators should already be rejecting routes with unusually long attributes.",
  "id": "GHSA-64c8-8qx9-25r7",
  "modified": "2026-06-02T18:31:34Z",
  "published": "2026-06-02T18:31:34Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-49943"
    },
    {
      "type": "WEB",
      "url": "https://bird.nic.cz"
    },
    {
      "type": "WEB",
      "url": "https://gitlab.nic.cz/labs/bird/-/blob/master/NEWS"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-49943 (GCVE-0-2026-49943)

Vulnerability from cvelistv5 – Published: 2026-06-02 16:16 – Updated: 2026-06-02 18:24

Summary

Severity

6.3 (Medium)


                        
                          CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:N/I:N/A:H

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

CWE-121 - Stack-based Buffer Overflow

Assigner

mitre

References

2 references

URL	Tags
https://bird.nic.cz
https://gitlab.nic.cz/labs/bird/-/blob/master/NEWS

Impacted products

1 product

Vendor	Product	Version
NIC	BIRD	Affected: 0 , ≤ 2.19.0 (semver)

Show details on NVD website

JSON

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                "id": "CVE-2026-49943",
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                  },
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                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
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                "timestamp": "2026-06-02T18:20:11.710969Z",
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        }
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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-64C8-8QX9-25R7

CVE-2026-49943 (GCVE-0-2026-49943)

Tags

Sightings

Nomenclature