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Fencer Vulns
medium 6.5

CVE-2026-46433 json

lldpd: Heap OOB Read in VLAN Decapsulation memmove

published 2026-06-09 5 mo ago modified 2026-07-23 3 mo ago also EUVD-2026-35858

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 13%
public exploits
0
none known

Summary

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.

Patch / fix

  • lldpd_project lldpd 1.0.22
  • lldpd Debian 14 1.0.22-1

debian advisories DEBIAN-CVE-2026-46433

  • lldpd openSUSE Leap 16.0 1.0.22-bp160.1.1
  • lldpd openSUSE Tumbleweed 1.0.22-1.1

opensuse advisories openSUSE-SU-2026:21146-1openSUSE-SU-2026:10794-1

  • lldpd Alpine 3.24, Alpine 3.23 1.0.22-r0

alpine advisories ALPINE-CVE-2026-46433

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • lldpd Azure Linux 3.0 1.0.22-1

azure linux advisories AZL-89700

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-46433 updated cvss 6.5

lldpd: lldpd: Denial of Service due to heap buffer over-read when processing VLAN-tagged Ethernet frames

  • Red Hat Enterprise Linux 8 lldpd Red Hat Enterprise Linux 9 lldpd Red Hat Enterprise Linux 10 lldpd
    affected: no fix available “Fix deferred”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
4 mo ago

Exploit prediction

0.22% chance of exploitation in the next 30 days, higher than 13% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 6.5 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • lldpd lldpd

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.