CVE-2018-5741
Update policies krb5-subdomain and ms-subdomain do not enforce controls promised in their documentation
- 6.5MediumCVSS base score
- 3.5%Exploitation in 30 daysEPSS · top 11% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
To provide fine-grained controls over the ability to use Dynamic DNS (DDNS) to update records in a zone, BIND 9 provides a feature called update-policy. Various rules can be configured to limit the types of updates that can be performed by a client, depending on the key used when sending the update request. Unfortunately, some rule types were not initially documented, and when documentation for them was added to the Administrator Reference Manual (ARM) in change #3112, the language that was added to the ARM at that time incorrectly described the behavior of two rule types, krb5-subdomain and ms-subdomain. This incorrect documentation could mislead operators into believing that policies they had configured were more restrictive than they actually were. This affects BIND versions prior to BIND 9.11.5 and BIND 9.12.3.
Timeline
ID reserved
By isc
- 12 months later
· 12 months later
Published
- 6 years later
· 6 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| iscCNA (assigner) | 3.0 | Medium6.5 | CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N |
| NVDNVD · Modified | 3.0 | Medium6.5 | CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N |
- EPSS (exploitation in 30 days)
- 3.5% · top 11% of all CVEs (9 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.5.
Affected products
What to do
Solution: At the time of public disclosure, ISC is not providing any code changing the behavior of the update-policy feature. While we believe that there are a few operators out there who are relying on the strictest interpretation permitted by the erroneous documentation, we have to balance that against changing the behavior of features in stable branches of BIND, including the 9.11 branch which is meant to be a feature-complete Extended Support Version of BIND 9. As a compromise between these conflicting priorities, we have decided that our best course of action is to disclose the error but leave the existing behavior of the krb5-subdomain and ms-subdomain policies as they are (while correcting the erroneous documentation). In maintenance releases issued during or after October 2018, the name field for ms-subdomain and krb5-subdomain will be corrected so that names lower than "." can be configured, and two new rule types will be added, krb5-selfsub and ms-selfsub, analogous to the existing selfsub rule type, which implement the behavior that was formerly described in the documentation for krb5-subdomain and ms-subdomain: restricting updates to names at or below the machine name encoded in the client's Windows or Kerberos principal.
Workaround: To limit updates to a subset of a zone -- for example, "sub.example.com" -- create a new "sub.example.com" child zone beneath "example.com", and set the desired update-policy in the child zone rather than the parent.
References
9
- 105379 (opens in a new tab)vdb-entryx_refsource_BIDx_transferred
- 1041674 (opens in a new tab)vdb-entryx_refsource_SECTRACKx_transferred
- https://kb.isc.org/docs/cve-2018-5741 (opens in a new tab)x_refsource_CONFIRMx_transferred
- GLSA-201903-13 (opens in a new tab)vendor-advisoryx_refsource_GENTOOx_transferred
- https://support.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbux03927en_us (opens in a new tab)x_refsource_CONFIRMx_transferred
- RHSA-2019:2057 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
- https://security.netapp.com/advisory/ntap-20190830-0001/ (opens in a new tab)x_refsource_CONFIRMx_transferred
- openSUSE-SU-2020:1699 (opens in a new tab)vendor-advisoryx_refsource_SUSEx_transferred
- openSUSE-SU-2020:1701 (opens in a new tab)vendor-advisoryx_refsource_SUSEx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2018-17510 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2018-5741)Record last updated .