SB2026062660 - Fedora 44 update for nsd
Published: June 26, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 4 vulnerabilities.
1) Heap-based buffer overflow (CVE-ID: CVE-2026-12244)
CWE-ID: CWE-122 - Heap-based Buffer Overflow
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
The vulnerability allows a remote user to execute arbitrary code.
The vulnerability exists due to a heap-based buffer overflow in SVCB RR handling when processing a crafted AXFR response containing a specially crafted SVCB RR. A remote user can send a crafted zone transfer response to execute arbitrary code.
Exploitation requires NSD to be configured as a secondary for a zone, and the malicious input must come from the configured primary for that zone.
2) Use-after-free (CVE-ID: CVE-2026-12245)
CWE-ID: CWE-416 - Use After Free
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to use-after-free in error logging on TLS connections when handling a DNS query over a DNS over TLS connection that is closed before the response is read. A remote attacker can send a DNS query over a DNS over TLS connection and close the connection early to cause a denial of service.
Only instances configured to use DNS over TLS are vulnerable.
3) Stack-based buffer overflow (CVE-ID: CVE-2026-12246)
CWE-ID: CWE-121 - Stack-based buffer overflow
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
The vulnerability allows a remote user to execute arbitrary code.
The vulnerability exists due to a stack-based buffer overflow in the APL RR rdata handling logic when writing a zonefile to disk. A remote user can provide a specially crafted APL resource record with an oversized adflength value to execute arbitrary code.
Exploitation requires control of data from a configured primary in a multi-tenant secondary DNS deployment.
4) Improper access control (CVE-ID: CVE-2026-12490)
CWE-ID: CWE-284 - Improper Access Control
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
The vulnerability allows a remote user to bypass client certificate-based access controls for zone transfers.
The vulnerability exists due to improper access control in the provide-xfr zone transfer authorization logic when handling zone transfer requests over the regular tls-port or regular TCP port. A remote user can request a zone transfer without presenting the required client certificate to bypass client certificate-based access controls for zone transfers.
Exploitation requires matching the other access control conditions of the provide-xfr rule, and the issue applies when tls-auth-xfr-only is not explicitly set to yes.
Remediation
Install update from vendor's website.