The CVE number for this vulnerability is CVE-2026-101341 = Summary When reading zone files, a specially crafted and formatted resource record containing a series of strings (TXT, NINFO, SPF, AVC, RESINFO and WALLET) can cause an out of bounds stack overwrite which can be exploited for executionof arbitrary commands. == Affected products NSD from and including version 4.10.0 up to and including version 4.15.2 == Description Tokens of text in RDATA (of for example TXT records) under 32 bytes are not checked to stay within the space reserved for the RDATA allowing for arbitrary sized out of bound stack writes, including an overwrite of a callback function pointer which is called directly after parse. Zone files which are written out by NSD itself, such for zones for which the NSD instance is secondary, will not be formatted like this. The zone file must be fed to NSD directly, (but it could come, for example, from an operator controlled provisioning system). == Mitigation === Downloading patched version NSD 4.15.3 is released with the patch https://nlnetlabs.nl/downloads/nsd/nsd-4.15.3.tar.gz === Applying the patch manually For NSD 4.15.2 the patch is: https://nlnetlabs.nl/downloads/nsd/patch_CVE-2026-101341.diff Apply the patch on the NSD source directory with: patch -p1 < patch_CVE-2026-101341.diff then run 'make install' to install NSD. The patch is tested to work on NSD 4.15.2. == Acknowledgments We would like to thank Alwaleed Ashi (LXR) , for discovering and responsibly disclosing the vulnerability.