Openvswitch: 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… (CVE-2026-46433)
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.
AI Analysis
Technical Summary
The vulnerability in lldpd (an implementation of IEEE 802.1ab LLDP) occurs in the lldpd_decode() function within src/daemon/lldpd.c. Prior to version 1.0.22, the function strips 802.1Q VLAN tags by shifting the frame payload 4 bytes left using memmove(). However, the byte count argument to memmove() is incorrectly calculated as s - 2 * ETHER_ADDR_LEN instead of s - 2 * ETHER_ADDR_LEN - 4. This results in a 4-byte heap buffer over-read past the allocated memory (malloc(h_mtu)) when the received frame size equals the interface MTU. The vulnerability is classified under CWE-125 (Out-of-bounds Read) and has a CVSS v3.1 base score of 6.5 (medium severity) with an impact on availability (denial of service). The issue has been patched in lldpd version 1.0.22.
Potential Impact
The vulnerability causes a heap buffer over-read of 4 bytes beyond the allocated buffer when processing Ethernet frames with 802.1Q VLAN tags at the interface MTU size. This can lead to a denial of service (application crash or instability) but does not impact confidentiality or integrity. There are no known exploits in the wild.
Mitigation Recommendations
Upgrade lldpd to version 1.0.22 or later, where this issue has been fixed. No other mitigation or workaround is indicated by the vendor advisory or source data.
Openvswitch: 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… (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.
CVSS v3.1
Score 6.5medium
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in lldpd (an implementation of IEEE 802.1ab LLDP) occurs in the lldpd_decode() function within src/daemon/lldpd.c. Prior to version 1.0.22, the function strips 802.1Q VLAN tags by shifting the frame payload 4 bytes left using memmove(). However, the byte count argument to memmove() is incorrectly calculated as s - 2 * ETHER_ADDR_LEN instead of s - 2 * ETHER_ADDR_LEN - 4. This results in a 4-byte heap buffer over-read past the allocated memory (malloc(h_mtu)) when the received frame size equals the interface MTU. The vulnerability is classified under CWE-125 (Out-of-bounds Read) and has a CVSS v3.1 base score of 6.5 (medium severity) with an impact on availability (denial of service). The issue has been patched in lldpd version 1.0.22.
Potential Impact
The vulnerability causes a heap buffer over-read of 4 bytes beyond the allocated buffer when processing Ethernet frames with 802.1Q VLAN tags at the interface MTU size. This can lead to a denial of service (application crash or instability) but does not impact confidentiality or integrity. There are no known exploits in the wild.
Mitigation Recommendations
Upgrade lldpd to version 1.0.22 or later, where this issue has been fixed. No other mitigation or workaround is indicated by the vendor advisory or source data.
Technical Details
- Gcve Source
- db.gcve.eu
- Csaf Category
- csaf_vex
- Csaf Version
- 2.0
- Publisher
- Microsoft Security Response Center
- Advisory Id
- msrc_CVE-2026-46433
- Cve Count
- 1
Threat ID: 6a2a7b489e049e7b7ee8d248
Added to database: 06/11/2026, 09:09:28 UTC
Last enriched: 08/07/2026, 02:25:16 UTC
Last updated: 09/13/2026, 22:01:34 UTC
Views: 189
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