CVE-2020-25685

See a problem?
Please try reporting it to the source first.
Source
https://cve.org/CVERecord?id=CVE-2020-25685
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2020-25685.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2020-25685
Downstream
Related
Published
2021-01-20T16:15:14.303Z
Modified
2026-03-15T22:35:07.890608Z
Severity
  • 3.7 (Low) CVSS_V3 - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N CVSS Calculator
Summary
[none]
Details

A flaw was found in dnsmasq before version 2.83. When getting a reply from a forwarded query, dnsmasq checks in forward.c:reply_query(), which is the forwarded query that matches the reply, by only using a weak hash of the query name. Due to the weak hash (CRC32 when dnsmasq is compiled without DNSSEC, SHA-1 when it is) this flaw allows an off-path attacker to find several different domains all having the same hash, substantially reducing the number of attempts they would have to perform to forge a reply and get it accepted by dnsmasq. This is in contrast with RFC5452, which specifies that the query name is one of the attributes of a query that must be used to match a reply. This flaw could be abused to perform a DNS Cache Poisoning attack. If chained with CVE-2020-25684 the attack complexity of a successful attack is reduced. The highest threat from this vulnerability is to data integrity.

References

Affected packages

Git /

Affected ranges

Database specific

unresolved_ranges 
[
    {
        "events": [
            {
                "introduced": "0"
            },
            {
                "fixed": "2.83"
            }
        ]
    },
    {
        "events": [
            {
                "introduced": "0"
            },
            {
                "last_affected": "32"
            }
        ]
    },
    {
        "events": [
            {
                "introduced": "0"
            },
            {
                "last_affected": "33"
            }
        ]
    },
    {
        "events": [
            {
                "introduced": "0"
            },
            {
                "last_affected": "10.0"
            }
        ]
    },
    {
        "events": [
            {
                "introduced": "4.21"
            },
            {
                "fixed": "4.21.14m"
            }
        ]
    },
    {
        "events": [
            {
                "introduced": "4.22"
            },
            {
                "fixed": "4.22.9m"
            }
        ]
    },
    {
        "events": [
            {
                "introduced": "4.23"
            },
            {
                "fixed": "4.23.7m"
            }
        ]
    },
    {
        "events": [
            {
                "introduced": "4.24"
            },
            {
                "fixed": "4.24.5m"
            }
        ]
    },
    {
        "events": [
            {
                "introduced": "4.25"
            },
            {
                "fixed": "4.25.2f"
            }
        ]
    },
    {
        "events": [
            {
                "introduced": "0"
            },
            {
                "fixed": "2.83"
            }
        ]
    }
]
source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2020-25685.json"