CVE-2026-89776 is a vulnerability in Linux Kernel
Published on September 16, 2026
vxlan: vnifilter: enforce exact length of GROUP/GROUP6 attributes
In the Linux kernel, the following vulnerability has been resolved:
vxlan: vnifilter: enforce exact length of GROUP/GROUP6 attributes
The VXLAN VNI filter entry policy declares the GROUP/GROUP6 address
attributes as NLA_BINARY with only a maximum length, so validate_nla()
accepts a payload shorter than the address. The GROUP consumer reads it
with nla_get_in_addr(), an unconditional 4-byte load, so a short
attribute over-reads up to 3 bytes of uninitialised slab data, which are
stored into remote_ip and echoed back via RTM_GETTUNNEL, disclosing
kernel memory.
Switch both entries to NLA_POLICY_EXACT_LEN() so the validator rejects
any GROUP/GROUP6 that is not exactly 4 / 16 bytes; a valid address is
always sent at full width.
Products Associated with CVE-2026-89776
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Affected Versions
Linux:- Version f9c4bb0b245cee35ef66f75bf409c9573d934cf9 and below e12c4663529699f457b2988c1dfedf4d13b3b3be is affected.
- Version f9c4bb0b245cee35ef66f75bf409c9573d934cf9 and below 47bfcc871576eaef6c8edab6749acd4b317306ea is affected.
- Version f9c4bb0b245cee35ef66f75bf409c9573d934cf9 and below a9ec10815199f9879ba080241dc555efb1daf324 is affected.
- Version f9c4bb0b245cee35ef66f75bf409c9573d934cf9 and below daebc7064a1b4c12c98e52c4bceede7f2fcd573c is affected.
- Version f9c4bb0b245cee35ef66f75bf409c9573d934cf9 and below ad32e564c62ebf5ba76dd60a22af52c69d54d17b is affected.
- Version f9c4bb0b245cee35ef66f75bf409c9573d934cf9 and below 984f831dda31b3a18f47454cf64989f65402879e is affected.
- Version 5.18 is affected.
- Before 5.18 is unaffected.
- Version 6.1.188, <= 6.1.* is unaffected.
- Version 6.6.157, <= 6.6.* is unaffected.
- Version 6.12.110, <= 6.12.* is unaffected.
- Version 6.18.52, <= 6.18.* is unaffected.
- Version 7.2.6, <= 7.2.* is unaffected.
- Version 7.3-rc1, <= * is unaffected.