CVE-2026-46433: lldpd: Heap OOB Read in VLAN Decapsulation memmove
lldpd is an implementation of IEEE 802.1ab (LLDP). Prior to version 1.0.22, lldpddecode() in src/daemon/lldpd.c strips 802.1Q VLAN tags from received Ethernet frames by calling memmove() to shift the frame payload 4 bytes left. The third argument (byte count) is s - 2 ETHERADDRLEN but should be s - 2 ETHERADDRLEN - 4, causing a 4-byte heap buffer over-read past the malloc(hmtu) allocation when the received frame size equals the interface MTU. This issue has been patched in version 1.0.22.
Other sources
lldpd: Heap OOB Read in VLAN Decapsulation memmove
— Microsoft
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 1.0.22-1 - Upgrade
Upgrade
lldpdto a version that resolves this vulnerability.Fixed in 1.0.22
Event History
Frequently Asked Questions
What is the severity of CVE-2026-46433?
CVE-2026-46433 has a severity rating of medium with a score of 6.5.
How do I fix CVE-2026-46433?
To mitigate CVE-2026-46433, upgrade to lldpd version 1.0.22 or later.
What type of vulnerability is CVE-2026-46433?
CVE-2026-46433 is categorized as a heap out-of-bounds read vulnerability in the lldpd implementation.
Which software is affected by CVE-2026-46433?
CVE-2026-46433 affects the lldpd software prior to version 1.0.22.
What exploit could CVE-2026-46433 lead to?
CVE-2026-46433 could potentially lead to information disclosure due to heap out-of-bounds reads.