Vulnerability Monitor

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CVE-2021-27853

Layer 2 network filtering capabilities such as IPv6 RA guard or ARP inspection can be bypassed using combinations of VLAN 0 headers and LLC/SNAP headers.

Published

2022-09-27T18:15:09.527

Last Modified

2025-05-21T16:15:24.957

Status

Modified

Source

[email protected]

Severity

CVSSv3.1: 4.7 (MEDIUM)

Weaknesses

Type: Secondary
CWE-290
Type: Primary
CWE-290

Affected Vendors & Products

Type	Vendor	Product	Version/Range	Vulnerable?
Application	ieee	ieee_802.2	≤ 802.2h-1997	Yes
Application	ietf	p802.1q	≤ d1.0	Yes
Operating System	cisco	catalyst_6503-e_firmware	15.5\(01.01.85\)sy07	Yes
Hardware	cisco	catalyst_6503-e	-	No
Operating System	cisco	catalyst_6504-e_firmware	15.5\(01.01.85\)sy07	Yes
Hardware	cisco	catalyst_6504-e	-	No
Operating System	cisco	catalyst_6506-e_firmware	15.5\(01.01.85\)sy07	Yes
Hardware	cisco	catalyst_6506-e	-	No
Operating System	cisco	catalyst_6509-e_firmware	15.5\(01.01.85\)sy07	Yes
Hardware	cisco	catalyst_6509-e	-	No
Operating System	cisco	catalyst_6509-neb-a_firmware	15.5\(01.01.85\)sy07	Yes
Hardware	cisco	catalyst_6509-neb-a	-	No
Operating System	cisco	catalyst_6509-v-e_firmware	15.5\(01.01.85\)sy07	Yes
Hardware	cisco	catalyst_6509-v-e	-	No
Operating System	cisco	catalyst_6513-e_firmware	15.5\(01.01.85\)sy07	Yes
Hardware	cisco	catalyst_6513-e	-	No
Operating System	cisco	catalyst_6807-xl_firmware	15.5\(01.01.85\)sy07	Yes
Hardware	cisco	catalyst_6807-xl	-	No
Operating System	cisco	catalyst_6840-x_firmware	15.5\(01.01.85\)sy07	Yes
Hardware	cisco	catalyst_6840-x	-	No
Operating System	cisco	catalyst_6880-x_firmware	15.5\(01.01.85\)sy07	Yes
Hardware	cisco	catalyst_6880-x	-	No
Operating System	cisco	catalyst_c6816-x-le_firmware	15.5\(01.01.85\)sy07	Yes
Hardware	cisco	catalyst_c6816-x-le	-	No
Operating System	cisco	catalyst_c6824-x-le-40g_firmware	15.5\(01.01.85\)sy07	Yes
Hardware	cisco	catalyst_c6824-x-le-40g	-	No
Operating System	cisco	catalyst_c6832-x-le_firmware	15.5\(01.01.85\)sy07	Yes
Hardware	cisco	catalyst_c6832-x-le	-	No
Operating System	cisco	catalyst_c6840-x-le-40g_firmware	15.5\(01.01.85\)sy07	Yes
Hardware	cisco	catalyst_c6840-x-le-40g	-	No
Operating System	cisco	catalyst_6800ia_firmware	15.5\(01.01.85\)sy07	Yes
Hardware	cisco	catalyst_6800ia	-	No
Application	cisco	ios_xe	17.3.3	Yes
Operating System	cisco	ios_xe	15.2\(07\)e02	Yes
Operating System	cisco	ios_xe	15.2\(07\)e03	Yes
Operating System	cisco	ios_xe	17.4.1	Yes
Operating System	cisco	ios_xe	17.6.1	Yes
Hardware	cisco	catalyst_3650-12x48fd-e	-	No
Hardware	cisco	catalyst_3650-12x48fd-l	-	No
Hardware	cisco	catalyst_3650-12x48fd-s	-	No
Hardware	cisco	catalyst_3650-12x48uq-e	-	No
Hardware	cisco	catalyst_3650-12x48uq-l	-	No
Hardware	cisco	catalyst_3650-12x48uq-s	-	No
Hardware	cisco	catalyst_3650-12x48ur-e	-	No
Hardware	cisco	catalyst_3650-12x48ur-l	-	No
Hardware	cisco	catalyst_3650-12x48ur-s	-	No
Hardware	cisco	catalyst_3650-12x48uz-e	-	No
Hardware	cisco	catalyst_3650-12x48uz-l	-	No
Hardware	cisco	catalyst_3650-12x48uz-s	-	No
Hardware	cisco	catalyst_3650-24pd-e	-	No
Hardware	cisco	catalyst_3650-24pd-l	-	No
Hardware	cisco	catalyst_3650-24pd-s	-	No
Hardware	cisco	catalyst_3650-24pdm-e	-	No
Hardware	cisco	catalyst_3650-24pdm-l	-	No
Hardware	cisco	catalyst_3650-24pdm-s	-	No
Hardware	cisco	catalyst_3650-24ps-e	-	No
Hardware	cisco	catalyst_3650-24ps-l	-	No
Hardware	cisco	catalyst_3650-24ps-s	-	No
Hardware	cisco	catalyst_3650-24td-e	-	No
Hardware	cisco	catalyst_3650-24td-l	-	No
Hardware	cisco	catalyst_3650-24td-s	-	No
Hardware	cisco	catalyst_3650-24ts-e	-	No
Hardware	cisco	catalyst_3650-24ts-l	-	No
Hardware	cisco	catalyst_3650-24ts-s	-	No
Hardware	cisco	catalyst_3650-48fd-e	-	No
Hardware	cisco	catalyst_3650-48fd-l	-	No
Hardware	cisco	catalyst_3650-48fd-s	-	No
Hardware	cisco	catalyst_3650-48fq-e	-	No
Hardware	cisco	catalyst_3650-48fq-l	-	No
Hardware	cisco	catalyst_3650-48fq-s	-	No
Hardware	cisco	catalyst_3650-48fqm-e	-	No
Hardware	cisco	catalyst_3650-48fqm-l	-	No
Hardware	cisco	catalyst_3650-48fqm-s	-	No
Hardware	cisco	catalyst_3650-48fs-e	-	No
Hardware	cisco	catalyst_3650-48fs-l	-	No
Hardware	cisco	catalyst_3650-48fs-s	-	No
Hardware	cisco	catalyst_3650-48pd-e	-	No
Hardware	cisco	catalyst_3650-48pd-l	-	No
Hardware	cisco	catalyst_3650-48pd-s	-	No
Hardware	cisco	catalyst_3650-48pq-e	-	No
Hardware	cisco	catalyst_3650-48pq-l	-	No
Hardware	cisco	catalyst_3650-48pq-s	-	No
Hardware	cisco	catalyst_3650-48ps-e	-	No
Hardware	cisco	catalyst_3650-48ps-l	-	No
Hardware	cisco	catalyst_3650-48ps-s	-	No
Hardware	cisco	catalyst_3650-48td-e	-	No
Hardware	cisco	catalyst_3650-48td-l	-	No
Hardware	cisco	catalyst_3650-48td-s	-	No
Hardware	cisco	catalyst_3650-48tq-e	-	No
Hardware	cisco	catalyst_3650-48tq-l	-	No
Hardware	cisco	catalyst_3650-48tq-s	-	No
Hardware	cisco	catalyst_3650-48ts-e	-	No
Hardware	cisco	catalyst_3650-48ts-l	-	No
Hardware	cisco	catalyst_3650-48ts-s	-	No
Hardware	cisco	catalyst_3650-8x24pd-e	-	No
Hardware	cisco	catalyst_3650-8x24pd-l	-	No
Hardware	cisco	catalyst_3650-8x24pd-s	-	No
Hardware	cisco	catalyst_3650-8x24uq-e	-	No
Hardware	cisco	catalyst_3650-8x24uq-l	-	No
Hardware	cisco	catalyst_3650-8x24uq-s	-	No
Hardware	cisco	catalyst_3850-12s-e	-	No
Hardware	cisco	catalyst_3850-12s-s	-	No
Hardware	cisco	catalyst_3850-12xs-e	-	No
Hardware	cisco	catalyst_3850-12xs-s	-	No
Hardware	cisco	catalyst_3850-16xs-e	-	No
Hardware	cisco	catalyst_3850-16xs-s	-	No
Hardware	cisco	catalyst_3850-24p-e	-	No
Hardware	cisco	catalyst_3850-24p-l	-	No
Hardware	cisco	catalyst_3850-24pw-s	-	No
Hardware	cisco	catalyst_3850-24s-e	-	No
Hardware	cisco	catalyst_3850-24s-s	-	No
Hardware	cisco	catalyst_3850-24t-e	-	No
Hardware	cisco	catalyst_3850-24t-l	-	No
Hardware	cisco	catalyst_3850-24t-s	-	No
Hardware	cisco	catalyst_3850-24u-e	-	No
Hardware	cisco	catalyst_3850-24u-l	-	No
Hardware	cisco	catalyst_3850-24u-s	-	No
Hardware	cisco	catalyst_3850-24xs-e	-	No
Hardware	cisco	catalyst_3850-24xs-s	-	No
Hardware	cisco	catalyst_3850-24xu-e	-	No
Hardware	cisco	catalyst_3850-24xu-l	-	No
Hardware	cisco	catalyst_3850-24xu-s	-	No
Hardware	cisco	catalyst_3850-32xs-e	-	No
Hardware	cisco	catalyst_3850-32xs-s	-	No
Hardware	cisco	catalyst_3850-48f-e	-	No
Hardware	cisco	catalyst_3850-48f-l	-	No
Hardware	cisco	catalyst_3850-48f-s	-	No
Hardware	cisco	catalyst_3850-48p-e	-	No
Hardware	cisco	catalyst_3850-48p-l	-	No
Hardware	cisco	catalyst_3850-48p-s	-	No
Hardware	cisco	catalyst_3850-48pw-s	-	No
Hardware	cisco	catalyst_3850-48t-e	-	No
Hardware	cisco	catalyst_3850-48t-l	-	No
Hardware	cisco	catalyst_3850-48t-s	-	No
Hardware	cisco	catalyst_3850-48u-e	-	No
Hardware	cisco	catalyst_3850-48u-l	-	No
Hardware	cisco	catalyst_3850-48u-s	-	No
Hardware	cisco	catalyst_3850-48xs-e	-	No
Hardware	cisco	catalyst_3850-48xs-f-e	-	No
Hardware	cisco	catalyst_3850-48xs-f-s	-	No
Hardware	cisco	catalyst_3850-48xs-s	-	No
Hardware	cisco	catalyst_9200	-	No
Hardware	cisco	catalyst_9200cx	-	No
Hardware	cisco	catalyst_9200l	-	No
Hardware	cisco	catalyst_9300	-	No
Hardware	cisco	catalyst_9300l	-	No
Hardware	cisco	catalyst_9300lm	-	No
Hardware	cisco	catalyst_9300x	-	No
Hardware	cisco	catalyst_9400	-	No
Hardware	cisco	catalyst_9500	-	No
Hardware	cisco	catalyst_9500h	-	No
Hardware	cisco	catalyst_9600	-	No
Hardware	cisco	catalyst_9600x	-	No
Hardware	cisco	catalyst_c3850-12x48u-e	-	No
Hardware	cisco	catalyst_c3850-12x48u-l	-	No
Hardware	cisco	catalyst_c3850-12x48u-s	-	No
Operating System	cisco	meraki_ms390_firmware	-	Yes
Hardware	cisco	meraki_ms390	-	No
Operating System	cisco	meraki_ms210_firmware	-	Yes
Hardware	cisco	meraki_ms210	-	No
Operating System	cisco	meraki_ms225_firmware	-	Yes
Hardware	cisco	meraki_ms225	-	No
Operating System	cisco	meraki_ms250_firmware	-	Yes
Hardware	cisco	meraki_ms250	-	No
Operating System	cisco	meraki_ms350_firmware	-	Yes
Hardware	cisco	meraki_ms350	-	No
Operating System	cisco	meraki_ms355_firmware	-	Yes
Hardware	cisco	meraki_ms355	-	No
Operating System	cisco	meraki_ms410_firmware	-	Yes
Hardware	cisco	meraki_ms410	-	No
Operating System	cisco	meraki_ms420_firmware	-	Yes
Hardware	cisco	meraki_ms420	-	No
Operating System	cisco	meraki_ms425_firmware	-	Yes
Hardware	cisco	meraki_ms425	-	No
Operating System	cisco	meraki_ms450_firmware	-	Yes
Hardware	cisco	meraki_ms450	-	No
Operating System	cisco	nexus_93180yc-ex_firmware	9.3\(5\)	Yes
Hardware	cisco	nexus_93180yc-ex	-	No
Operating System	cisco	nexus_93180yc-fx_firmware	9.3\(5\)	Yes
Hardware	cisco	nexus_93180yc-fx	-	No
Operating System	cisco	nexus_93180yc-fx3_firmware	9.3\(5\)	Yes
Hardware	cisco	nexus_93180yc-fx3	-	No
Operating System	cisco	nexus_93240yc-fx2_firmware	9.3\(5\)	Yes
Hardware	cisco	nexus_93240yc-fx2	-	No
Operating System	cisco	nexus_93360yc-fx2_firmware	9.3\(5\)	Yes
Hardware	cisco	nexus_93360yc-fx2	-	No
Operating System	cisco	nexus_93120tx_firmware	9.3\(5\)	Yes
Hardware	cisco	nexus_93120tx	-	No
Operating System	cisco	nexus_93108tc-ex_firmware	9.3\(5\)	Yes
Hardware	cisco	nexus_93108tc-ex	-	No
Operating System	cisco	nexus_9348gc-fxp_firmware	9.3\(5\)	Yes
Hardware	cisco	nexus_9348gc-fxp	-	No
Operating System	cisco	nexus_93108tc-fx_firmware	9.3\(5\)	Yes
Hardware	cisco	nexus_93108tc-fx	-	No
Operating System	cisco	nexus_93108tc-fx3p_firmware	9.3\(5\)	Yes
Hardware	cisco	nexus_93108tc-fx3p	-	No
Operating System	cisco	nexus_93216tc-fx2_firmware	9.3\(5\)	Yes
Hardware	cisco	nexus_93216tc-fx2	-	No
Operating System	cisco	n9k-c9316d-gx_firmware	9.3\(5\)	Yes
Hardware	cisco	n9k-c9316d-gx	-	No
Operating System	cisco	n9k-c93600cd-gx_firmware	9.3\(5\)	Yes
Hardware	cisco	n9k-c93600cd-gx	-	No
Operating System	cisco	n9k-c9332d-gx2b_firmware	9.3\(5\)	Yes
Hardware	cisco	n9k-c9332d-gx2b	-	No
Operating System	cisco	n9k-c9348d-gx2a_firmware	9.3\(5\)	Yes
Hardware	cisco	n9k-c9348d-gx2a	-	No
Operating System	cisco	n9k-c9364d-gx2a_firmware	9.3\(5\)	Yes
Hardware	cisco	n9k-c9364d-gx2a	-	No
Operating System	cisco	n9k-x97160yc-ex_firmware	9.3\(5\)	Yes
Hardware	cisco	n9k-x97160yc-ex	-	No
Operating System	cisco	n9k-x9788tc-fx_firmware	9.3\(5\)	Yes
Hardware	cisco	n9k-x9788tc-fx	-	No
Operating System	cisco	n9k-x9564px_firmware	9.3\(5\)	Yes
Hardware	cisco	n9k-x9564px	-	No
Operating System	cisco	n9k-x9464px_firmware	9.3\(5\)	Yes
Hardware	cisco	n9k-x9464px	-	No
Operating System	cisco	n9k-x9564tx_firmware	9.3\(5\)	Yes
Hardware	cisco	n9k-x9564tx	-	No
Operating System	cisco	n9k-x9464tx2_firmware	9.3\(5\)	Yes
Hardware	cisco	n9k-x9464tx2	-	No
Operating System	cisco	nexus_9636pq_firmware	9.3\(5\)	Yes
Hardware	cisco	nexus_9636pq	-	No
Operating System	cisco	nexus_x9636q-r_firmware	9.3\(5\)	Yes
Hardware	cisco	nexus_x9636q-r	-	No
Operating System	cisco	nexus_9536pq_firmware	9.3\(5\)	Yes
Hardware	cisco	nexus_9536pq	-	No
Operating System	cisco	nexus_9432pq_firmware	9.3\(5\)	Yes
Hardware	cisco	nexus_9432pq	-	No
Operating System	cisco	nexus_9736pq_firmware	9.3\(5\)	Yes
Hardware	cisco	nexus_9736pq	-	No
Operating System	cisco	n9k-x9736c-fx_firmware	9.3\(5\)	Yes
Hardware	cisco	n9k-x9736c-fx	-	No
Operating System	cisco	n9k-x9732c-ex_firmware	9.3\(5\)	Yes
Hardware	cisco	n9k-x9732c-ex	-	No
Operating System	cisco	n9k-x9732c-fx_firmware	9.3\(5\)	Yes
Hardware	cisco	n9k-x9732c-fx	-	No
Operating System	cisco	n9k-x9736c-ex_firmware	9.3\(5\)	Yes
Hardware	cisco	n9k-x9736c-ex	-	No
Operating System	cisco	n9k-x9636c-rx_firmware	9.3\(5\)	Yes
Hardware	cisco	n9k-x9636c-rx	-	No
Operating System	cisco	n9k-x9636c-r_firmware	9.3\(5\)	Yes
Hardware	cisco	n9k-x9636c-r	-	No
Operating System	cisco	n9k-x9432c-s_firmware	9.3\(5\)	Yes
Hardware	cisco	n9k-x9432c-s	-	No
Operating System	cisco	nexus_9716d-gx_firmware	9.3\(5\)	Yes
Hardware	cisco	nexus_9716d-gx	-	No
Operating System	cisco	nexus_9504_firmware	9.3\(5\)	Yes
Hardware	cisco	nexus_9504	-	No
Operating System	cisco	nexus_9508_firmware	9.3\(5\)	Yes
Hardware	cisco	nexus_9508	-	No
Operating System	cisco	nexus_9516_firmware	9.3\(5\)	Yes
Hardware	cisco	nexus_9516	-	No
Operating System	cisco	nexus_92160yc-x_firmware	9.3\(5\)	Yes
Hardware	cisco	nexus_92160yc-x	-	No
Operating System	cisco	nexus_9272q_firmware	9.3\(5\)	Yes
Hardware	cisco	nexus_9272q	-	No
Operating System	cisco	nexus_92304qc_firmware	9.3\(5\)	Yes
Hardware	cisco	nexus_92304qc	-	No
Operating System	cisco	nexus_9236c_firmware	9.3\(5\)	Yes
Hardware	cisco	nexus_9236c	-	No
Operating System	cisco	nexus_92300yc_firmware	9.3\(5\)	Yes
Hardware	cisco	nexus_92300yc	-	No
Operating System	cisco	nexus_92348gc-x_firmware	9.3\(5\)	Yes
Hardware	cisco	nexus_92348gc-x	-	No
Operating System	cisco	nexus_9364c_firmware	9.3\(5\)	Yes
Hardware	cisco	nexus_9364c	-	No
Operating System	cisco	nexus_9336c-fx2_firmware	9.3\(5\)	Yes
Hardware	cisco	nexus_9336c-fx2	-	No
Operating System	cisco	nexus_9336c-fx2-e_firmware	9.3\(5\)	Yes
Hardware	cisco	nexus_9336c-fx2-e	-	No
Operating System	cisco	nexus_9332c_firmware	9.3\(5\)	Yes
Hardware	cisco	nexus_9332c	-	No
Operating System	cisco	nexus_9364c-gx_firmware	9.3\(5\)	Yes
Hardware	cisco	nexus_9364c-gx	-	No
Operating System	cisco	nexus_9800_firmware	9.3\(5\)	Yes
Hardware	cisco	nexus_9800	-	No
Operating System	cisco	sf500-24_firmware	3.0.0.61	Yes
Hardware	cisco	sf500-24	-	No
Operating System	cisco	sf-500-24mp_firmware	3.0.0.61	Yes
Hardware	cisco	sf-500-24mp	-	No
Operating System	cisco	sf500-24p_firmware	3.0.0.61	Yes
Hardware	cisco	sf500-24p	-	No
Operating System	cisco	sf500-48_firmware	3.0.0.61	Yes
Hardware	cisco	sf500-48	-	No
Operating System	cisco	sf500-48mp_firmware	3.0.0.61	Yes
Hardware	cisco	sf500-48mp	-	No
Operating System	cisco	sf500-18p_firmware	3.0.0.61	Yes
Hardware	cisco	sf500-18p	-	No
Operating System	cisco	sg500-28_firmware	3.0.0.61	Yes
Hardware	cisco	sg500-28	-	No
Operating System	cisco	sg500-28mpp_firmware	3.0.0.61	Yes
Hardware	cisco	sg500-28mpp	-	No
Operating System	cisco	sg500-28p_firmware	3.0.0.61	Yes
Hardware	cisco	sg500-28p	-	No
Operating System	cisco	sg500-52_firmware	3.0.0.61	Yes
Hardware	cisco	sg500-52	-	No
Operating System	cisco	sg500-52mp_firmware	3.0.0.61	Yes
Hardware	cisco	sg500-52mp	-	No
Operating System	cisco	sg500-52p_firmware	3.0.0.61	Yes
Hardware	cisco	sg500-52p	-	No
Operating System	cisco	sg500x-24_firmware	3.0.0.61	Yes
Hardware	cisco	sg500x-24	-	No
Operating System	cisco	sg500x-24mpp_firmware	3.0.0.61	Yes
Hardware	cisco	sg500x-24mpp	-	No
Operating System	cisco	sg500x-24p_firmware	3.0.0.61	Yes
Hardware	cisco	sg500x-24p	-	No
Operating System	cisco	sg500x-48_firmware	3.0.0.61	Yes
Hardware	cisco	sg500x-48	-	No
Operating System	cisco	sg500x-48mpp_firmware	3.0.0.61	Yes
Hardware	cisco	sg500x-48mpp	-	No
Operating System	cisco	sg500x-48p_firmware	3.0.0.61	Yes
Hardware	cisco	sg500x-48p	-	No

References

https://blog.champtar.fr/VLAN0_LLC_SNAP/ Exploit, Third Party Advisory ([email protected])
https://datatracker.ietf.org/doc/draft-ietf-v6ops-ra-guard/08/ Technical Description, Third Party Advisory ([email protected])
https://kb.cert.org/vuls/id/855201 Third Party Advisory, US Government Resource ([email protected])
https://standards.ieee.org/ieee/802.1Q/10323/ Vendor Advisory ([email protected])
https://standards.ieee.org/ieee/802.2/1048/ Vendor Advisory ([email protected])
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-VU855201-J3z8CKTX Third Party Advisory ([email protected])
https://blog.champtar.fr/VLAN0_LLC_SNAP/ Exploit, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://datatracker.ietf.org/doc/draft-ietf-v6ops-ra-guard/08/ Technical Description, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://kb.cert.org/vuls/id/855201 Third Party Advisory, US Government Resource (af854a3a-2127-422b-91ae-364da2661108)
https://standards.ieee.org/ieee/802.1Q/10323/ Vendor Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://standards.ieee.org/ieee/802.2/1048/ Vendor Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-VU855201-J3z8CKTX Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)