# CVE-2026-46433: lldpd: Heap OOB Read in VLAN Decapsulation memmove

CVE-2026-46433 is fixed in lldpd on 1 platform, first by DEBIAN-CVE-2026-46433, released May 27, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-46433
- Priority: Routine
- CVSS: 6.5 (Moderate)
- EPSS: 0.0023
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jun 9, 2026
- Weakness: Out-of-bounds Read
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-46433

## Description

lldpd is an implementation of IEEE 802.1ab (LLDP). Prior to version 1.0.22, lldpd_decode() 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 * ETHER_ADDR_LEN but should be s - 2 * ETHER_ADDR_LEN - 4, causing a 4-byte heap buffer over-read past the malloc(h_mtu) allocation when the received frame size equals the interface MTU. This issue has been patched in version 1.0.22.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | lldpd Debian 14 | 1.0.22-1 | [DEBIAN-CVE-2026-46433](https://patchblox.com/security/data/fix/linux/debian-cve-2026-46433.md) | May 27, 2026 |
| Linux | lldpd opensuse-leap 16.0 | 1.0.22-bp160.1.1 | [OPENSUSE-SU-2026:21146-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21146-1.md) | Jun 22, 2026 |

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Data as of 2026-11-08T06:59:42Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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