CVE-2018-5738
The intended (and documented) behavior is that if an operator has not specified a value for the "allow-recursion" setting, it SHOULD default to one of the following: none, if "recursion no;" is set in named.conf; a value inherited from the…
Does this matter?
EPSS puts the probability of exploitation in the next 30 days at 11.2%, higher than 96% of all known CVEs. Patch or mitigate before the next change window.
Description
Change #4777 (introduced in October 2017) introduced an unforeseen issue in releases which were issued after that date, affecting which clients are permitted to make recursive queries to a BIND nameserver. The intended (and documented) behavior is that if an operator has not specified a value for the "allow-recursion" setting, it SHOULD default to one of the following: none, if "recursion no;" is set in named.conf; a value inherited from the "allow-query-cache" or "allow-query" settings IF "recursion yes;" (the default for that setting) AND match lists are explicitly set for "allow-query-cache" or "allow-query" (see the BIND9 Administrative Reference Manual section 6.2 for more details); or the intended default of "allow-recursion {localhost; localnets;};" if "recursion yes;" is in effect and no values are explicitly set for "allow-query-cache" or "allow-query". However, because of the regression introduced by change #4777, it is possible when "recursion yes;" is in effect and no match list values are provided for "allow-query-cache" or "allow-query" for the setting of "allow-recursion" to inherit a setting of all hosts from the "allow-query" setting default, improperly permitting recursion to all clients. Affects BIND 9.9.12, 9.10.7, 9.11.3, 9.12.0->9.12.1-P2, the development release 9.13.0, and also releases 9.9.12-S1, 9.10.7-S1, 9.11.3-S1, and 9.11.3-S2 from BIND 9 Supported Preview Edition.
- CVSS 3.0
- 7.5 HIGHCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- EPSS
- 11.16% probability · 96th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-200
- Affected
- isc/bind · canonical/ubuntu linux
- Source
- security-officer@isc.org
EPSS 11.2% since 27 October 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- http://www.securitytracker.com/id/1041115Third Party Advisory, VDB Entry
- https://kb.isc.org/docs/aa-01616Mitigation, Vendor Advisory
- https://security.gentoo.org/glsa/201903-13Third Party Advisory
- https://security.netapp.com/advisory/ntap-20190830-0002/
- https://usn.ubuntu.com/3683-1/Third Party Advisory
- http://www.securitytracker.com/id/1041115Third Party Advisory, VDB Entry
- https://kb.isc.org/docs/aa-01616Mitigation, Vendor Advisory
- https://security.gentoo.org/glsa/201903-13Third Party Advisory
- https://security.netapp.com/advisory/ntap-20190830-0002/
- https://usn.ubuntu.com/3683-1/Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.