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CVE-2026-53003

Updated on 24 Jun 2026

Severity

7.5 High severity

Details

CVSS score
7.5
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Links
NISTCIRCLRHELUbuntu

Overview

About vulnerability

In the Linux kernel, the following vulnerability has been resolved:

pppoe: drop PFC frames

RFC 2516 Section 7 states that Protocol Field Compression (PFC) is NOT RECOMMENDED for PPPoE. In practice, pppd does not support negotiating PFC for PPPoE sessions, and the current PPPoE driver assumes an uncompressed (2-byte) protocol field. However, the generic PPP layer function ppp_input() is not aware of the negotiation result, and still accepts PFC frames.

If a peer with a broken implementation or an attacker sends a frame with a compressed (1-byte) protocol field, the subsequent PPP payload is shifted by one byte. This causes the network header to be 4-byte misaligned, which may trigger unaligned access exceptions on some architectures.

To reduce the attack surface, drop PPPoE PFC frames. Introduce ppp_skb_is_compressed_proto() helper function to be used in both ppp_generic.c and pppoe.c to avoid open-coding.

Details

Affected product:
AlmaLinux 9.2 ESU , Amazon Linux 2 ELS , Oracle Linux 7 ELS , TuxCare 9.6 ESU , Ubuntu 20.04 ELS
Affected packages:
linux-meta @ 5.4.0 (+5 more)

Fixes

KernelCare state

Live-patch status from KernelCare for each operating system.

Operating system Status Covered kernels
AlmaLinux 9.2 ESU Planned —
Amazon Linux 2023 Planned —
Debian 11 Released
37 kernels
  • 5.10.46-5
  • 5.10.70-1
  • 5.10.46-4
  • 5.10.84-1
  • 5.10.92-1
  • 5.10.92-2
  • 5.10.103-1
  • 5.10.106-1
  • 5.10.113-1
  • 5.10.120-1
  • 5.10.127-1
  • 5.10.127-2
  • 5.10.136-1
  • 5.10.140-1
  • 5.10.149-1
  • 5.10.149-2
  • 5.10.158-2
  • 5.10.162-1
  • 5.10.179-1
  • 5.10.179-2
  • 5.10.179-3
  • 5.10.179-5
  • 5.10.191-1
  • 5.10.197-1
  • 5.10.178-3
  • 5.10.205-2
  • 5.10.205-1
  • 5.10.209-2
  • 5.10.216-1
  • 5.10.218-1
  • 5.10.221-1
  • 5.10.223-1
  • 5.10.226-1
  • 5.10.234-1
  • 5.10.237-1
  • 5.10.244-1
  • 5.10.247-1
Debian 11 cloud Released
17 kernels
  • 5.10.113-1
  • 5.10.179-2
  • 5.10.179-3
  • 5.10.179-5
  • 5.10.191-1
  • 5.10.197-1
  • 5.10.205-2
  • 5.10.209-2
  • 5.10.216-1
  • 5.10.218-1
  • 5.10.221-1
  • 5.10.223-1
  • 5.10.226-1
  • 5.10.234-1
  • 5.10.237-1
  • 5.10.244-1
  • 5.10.247-1
Debian 12 Released
40 kernels
  • 6.1.38-1
  • 6.1.38-2
  • 6.1.38-4
  • 6.1.52-1
  • 6.1.55-1
  • 6.1.64-1
  • 6.1.66-1
  • 6.1.69-1
  • 6.1.76-1
  • 6.1.27-1
  • 6.1.67-1
  • 6.1.85-1
  • 6.1.90-1
  • 6.1.94-1
  • 6.1.99-1
  • 6.1.106-3
  • 6.1.112-1
  • 6.1.115-1
  • 6.1.119-1
  • 6.1.123-1
  • 6.1.128-1
  • 6.1.124-1
  • 6.1.129-1
  • 6.1.133-1
  • 6.1.135-1
  • 6.1.137-1
  • 6.1.140-1
  • 6.1.139-1
  • 6.1.147-1
  • 6.1.148-1
  • 6.1.153-1
  • 6.1.158-1
  • 6.1.159-1
  • 6.1.162-1
  • 6.1.164-1
  • 6.1.170-1
  • 6.1.170-3
  • 6.1.172-1
  • 6.1.174-1
  • 6.1.170-2
Debian 13 Released
10 kernels
  • 6.12.85-1
  • 6.12.86-1
  • 6.12.88-1
  • 6.12.74-2
  • 6.12.73-1
  • 6.12.63-1
  • 6.12.69-1
  • 6.12.74-1
  • 6.12.90-1
  • 6.12.90-2
Proxmox VE 7 5.15 Released
47 kernels
  • 5.15.5-1-pve-5.15.5-1
  • 5.15.12-1-pve-5.15.12-2
  • 5.15.12-1-pve-5.15.12-3
  • 5.15.17-1-pve-5.15.17-1
  • 5.15.19-1-pve-5.15.19-1
  • 5.15.19-2-pve-5.15.19-2
  • 5.15.19-2-pve-5.15.19-3
  • 5.15.27-1-pve-5.15.27-1
  • 5.15.30-1-pve-5.15.30-1
  • 5.15.30-2-pve-5.15.30-3
  • 5.15.35-1-pve-5.15.35-1
  • 5.15.35-1-pve-5.15.35-2
  • 5.15.35-1-pve-5.15.35-3
  • 5.15.35-2-pve-5.15.35-4
  • 5.15.35-2-pve-5.15.35-5
  • 5.15.35-3-pve-5.15.35-6
  • 5.15.39-1-pve-5.15.39-1
  • 5.15.39-2-pve-5.15.39-2
  • 5.15.39-3-pve-5.15.39-3
  • 5.15.39-4-pve-5.15.39-4
  • 5.15.7-1-pve-5.15.7-1
  • 5.15.53-1-pve-5.15.53-1
  • 5.15.60-1-pve-5.15.60-1
  • 5.15.60-2-pve-5.15.60-2
  • 5.15.64-1-pve-5.15.64-1
  • 5.15.74-1-pve-5.15.74-1
  • 5.15.83-1-pve-5.15.83-1
  • 5.15.102-1-pve-5.15.102-1
  • 5.15.104-1-pve-5.15.104-1
  • 5.15.104-1-pve-5.15.104-2
  • 5.15.107-1-pve-5.15.107-1
  • 5.15.107-2-pve-5.15.107-2
  • 5.15.85-1-pve-5.15.85-1
  • 5.15.108-1-pve-5.15.108-1
  • 5.15.108-1-pve-5.15.108-2
  • 5.15.116-1-pve-5.15.116-1
  • 5.15.126-1-pve-5.15.126-1
  • 5.15.131-1-pve-5.15.131-1
  • 5.15.131-1-pve-5.15.131-2
  • 5.15.131-2-pve-5.15.131-3
  • 5.15.136-1-pve-5.15.136-1
  • 5.15.111-1-pve-5.15.111-1
  • 5.15.143-1-pve-5.15.143-1
  • 5.15.149-1-pve-5.15.149-1
  • 5.15.152-1-pve-5.15.152-1
  • 5.15.158-1-pve_5.15.158-1
  • 5.15.158-2-pve_5.15.158-2
Ubuntu 20.04 HWE AWS Released
57 kernels
  • 5.15.0-1026.30~20.04.2
  • 5.15.0-1022.26~20.04.1
  • 5.15.0-1023.27~20.04.1
  • 5.15.0-1021.25~20.04.1
  • 5.15.0-1020.24~20.04.1
  • 5.15.0-1017.21~20.04.1
  • 5.15.0-1019.23~20.04.1
  • 5.15.0-1014.18~20.04.1
  • 5.15.0-1015.19~20.04.1
  • 5.15.0-1018.22~20.04.1
  • 5.15.0-1027.31~20.04.1
  • 5.15.0-1028.32~20.04.1
  • 5.15.0-1030.34~20.04.1
  • 5.15.0-1031.35~20.04.1
  • 5.15.0-1033.37~20.04.1
  • 5.15.0-1034.38~20.04.1
  • 5.15.0-1035.39~20.04.1
  • 5.15.0-1036.40~20.04.1
  • 5.15.0-1037.41~20.04.1
  • 5.15.0-1038.43~20.04.1
  • 5.15.0-1039.44~20.04.1
  • 5.15.0-1040.45~20.04.1
  • 5.15.0-1041.46~20.04.1
  • 5.15.0-1043.48~20.04.1
  • 5.15.0-1044.49~20.04.1
  • 5.15.0-1045.50~20.04.1
  • 5.15.0-1047.52~20.04.1
  • 5.15.0-1048.53~20.04.1
  • 5.15.0-1049.54~20.04.1
  • 5.15.0-1050.55~20.04.1
  • 5.15.0-1051.56~20.04.1
  • 5.15.0-1052.57~20.04.1
  • 5.15.0-1053.58~20.04.1
  • 5.15.0-1055.60~20.04.1
  • 5.15.0-1056.61~20.04.1
  • 5.15.0-1057.63~20.04.1
  • 5.15.0-1058.64~20.04.1
  • 5.15.0-1061.67~20.04.1
  • 5.15.0-1062.68~20.04.1
  • 5.15.0-1063.69~20.04.1
  • 5.15.0-1064.70~20.04.1
  • 5.15.0-1065.71~20.04.1
  • 5.15.0-1066.72~20.04.1
  • 5.15.0-1067.73~20.04.1
  • 5.15.0-1068.74~20.04.1
  • 5.15.0-1069.75~20.04.1
  • 5.15.0-1070.76~20.04.1
  • 5.15.0-1071.77~20.04.1
  • 5.15.0-1072.78~20.04.1
  • 5.15.0-1073.79~20.04.1
  • 5.15.0-1075.82~20.04.1
  • 5.15.0-1077.84~20.04.1
  • 5.15.0-1080.87~20.04.1
  • 5.15.0-1081.88~20.04.1
  • 5.15.0-1082.89~20.04.1
  • 5.15.0-1083.90~20.04.1
  • 5.15.0-1084.91~20.04.1
Ubuntu 20.04 HWE Azure Released
40 kernels
  • 5.15.0-1029.36~20.04.1
  • 5.15.0-1022.27~20.04.1
  • 5.15.0-1023.29~20.04.1
  • 5.15.0-1021.26~20.04.1
  • 5.15.0-1020.25~20.04.1
  • 5.15.0-1017.20~20.04.1
  • 5.15.0-1019.24~20.04.1
  • 5.15.0-1008.9~20.04.1
  • 5.15.0-1013.16~20.04.1
  • 5.15.0-1014.17~20.04.1
  • 5.15.0-1024.30~20.04.1
  • 5.15.0-1034.41~20.04.1
  • 5.15.0-1049.56~20.04.1
  • 5.15.0-1050.57~20.04.1
  • 5.15.0-1054.62~20.04.1
  • 5.15.0-1056.64~20.04.1
  • 5.15.0-1057.65~20.04.1
  • 5.15.0-1058.66~20.04.2
  • 5.15.0-1059.67~20.04.1
  • 5.15.0-1060.69~20.04.1
  • 5.15.0-1061.70~20.04.1
  • 5.15.0-1063.72~20.04.1
  • 5.15.0-1064.73~20.04.1
  • 5.15.0-1067.76~20.04.1
  • 5.15.0-1068.77~20.04.1
  • 5.15.0-1065.74~20.04.1
  • 5.15.0-1070.79~20.04.1
  • 5.15.0-1071.80~20.04.1
  • 5.15.0-1072.81~20.04.1
  • 5.15.0-1073.82~20.04.1
  • 5.15.0-1074.83~20.04.1
  • 5.15.0-1075.84~20.04.1
  • 5.15.0-1078.87~20.04.1
  • 5.15.0-1079.88~20.04.1
  • 5.15.0-1081.90~20.04.1
  • 5.15.0-1082.91~20.04.1
  • 5.15.0-1086.95~20.04.1
  • 5.15.0-1087.96~20.04.1
  • 5.15.0-1088.97~20.04.1
  • 5.15.0-1089.98~20.04.1
Ubuntu 22.04 Released
97 kernels
  • 5.15.0-27.28
  • 5.15.0-33.34
  • 5.15.0-37.39
  • 5.15.0-39.42
  • 5.15.0-25.25
  • 5.15.0-28.29
  • 5.15.0-29.30
  • 5.15.0-30.31
  • 5.15.0-41.44
  • 5.15.0-43.46
  • 5.15.0-46.49
  • 5.15.0-35.36
  • 5.15.0-47.51
  • 5.15.0-48.54
  • 5.15.0-40.43
  • 5.15.0-50.56
  • 5.15.0-52.58
  • 5.15.0-53.59
  • 5.15.0-56.62
  • 5.15.0-54.60
  • 5.15.0-57.63
  • 5.15.0-58.64
  • 5.15.0-60.66
  • 5.15.0-67.74
  • 5.15.0-69.76
  • 5.15.0-70.77
  • 5.15.0-71.78
  • 5.15.0-72.79
  • 5.15.0-68.75
  • 5.15.0-73.80
  • 5.15.0-75.82
  • 5.15.0-76.83
  • 5.15.0-78.85
  • 5.15.0-79.86
  • 5.15.0-82.91
  • 5.15.0-83.92
  • 5.15.0-84.93
  • 5.15.0-86.96
  • 5.15.0-74.81
  • 5.15.0-87.97
  • 5.15.0-88.98
  • 5.15.0-89.99
  • 5.15.0-91.101
  • 5.15.0-92.102
  • 5.15.0-94.104
  • 5.15.0-97.107
  • 5.15.0-100.110
  • 5.15.0-101.111
  • 5.15.0-102.112
  • 5.15.0-105.115
  • 5.15.0-106.116
  • 5.15.0-107.117
  • 5.15.0-112.122
  • 5.15.0-113.123
  • 5.15.0-116.126
  • 5.15.0-117.127
  • 5.15.0-118.128
  • 5.15.0-119.129
  • 5.15.0-121.131
  • 5.15.0-122.132
  • 5.15.0-124.134
  • 5.15.0-125.135
  • 5.15.0-127.137
  • 5.15.0-130.140
  • 5.15.0-126.136
  • 5.15.0-131.141
  • 5.15.0-128.138
  • 5.15.0-133.144
  • 5.15.0-134.145
  • 5.15.0-135.146
  • 5.15.0-136.147
  • 5.15.0-138.148
  • 5.15.0-139.149
  • 5.15.0-140.150
  • 5.15.0-141.151
  • 5.15.0-142.152
  • 5.15.0-143.153
  • 5.15.0-144.157
  • 5.15.0-151.161
  • 5.15.0-152.162
  • 5.15.0-153.163
  • 5.15.0-156.166
  • 5.15.0-157.167
  • 5.15.0-160.170
  • 5.15.0-161.171
  • 5.15.0-163.173
  • 5.15.0-164.174
  • 5.15.0-168.178
  • 5.15.0-170.180
  • 5.15.0-171.181
  • 5.15.0-173.183
  • 5.15.0-174.184
  • 5.15.0-176.186
  • 5.15.0-177.187
  • 5.15.0-179.189
  • 5.15.0-181.191
  • 5.15.0-185.195
Ubuntu 22.04 AWS Released
88 kernels
  • 5.15.0-1005.7
  • 5.15.0-1008.10
  • 5.15.0-1011.14
  • 5.15.0-1013.17
  • 5.15.0-1015.19
  • 5.15.0-1017.21
  • 5.15.0-1009.11
  • 5.15.0-1020.24
  • 5.15.0-1021.25
  • 5.15.0-1022.26
  • 5.15.0-1023.27
  • 5.15.0-1026.30
  • 5.15.0-1004.6
  • 5.15.0-1014.18
  • 5.15.0-1018.22
  • 5.15.0-1024.29
  • 5.15.0-1027.31
  • 5.15.0-1028.32
  • 5.15.0-1030.34
  • 5.15.0-1031.35
  • 5.15.0-1033.37
  • 5.15.0-1034.38
  • 5.15.0-1035.39
  • 5.15.0-1036.40
  • 5.15.0-1032.36
  • 5.15.0-1037.41
  • 5.15.0-1038.43
  • 5.15.0-1039.44
  • 5.15.0-1040.45
  • 5.15.0-1042.47
  • 5.15.0-1043.48
  • 5.15.0-1044.49
  • 5.15.0-1045.50
  • 5.15.0-1047.52
  • 5.15.0-1048.53
  • 5.15.0-1049.54
  • 5.15.0-1050.55
  • 5.15.0-1051.56
  • 5.15.0-1052.57
  • 5.15.0-1053.58
  • 5.15.0-1055.60
  • 5.15.0-1056.61
  • 5.15.0-1057.63
  • 5.15.0-1060.66
  • 5.15.0-1061.67
  • 5.15.0-1062.68
  • 5.15.0-1063.69
  • 5.15.0-1064.70
  • 5.15.0-1065.71
  • 5.15.0-1066.72
  • 5.15.0-1067.73
  • 5.15.0-1068.74
  • 5.15.0-1069.75
  • 5.15.0-1070.76
  • 5.15.0-1071.77
  • 5.15.0-1072.78
  • 5.15.0-1073.79
  • 5.15.0-1076.83
  • 5.15.0-1078.85
  • 5.15.0-1079.86
  • 5.15.0-1080.87
  • 5.15.0-1081.88
  • 5.15.0-1082.89
  • 5.15.0-1083.90
  • 5.15.0-1084.91
  • 5.15.0-1085.92
  • 5.15.0-1086.93
  • 5.15.0-1087.94
  • 5.15.0-1088.95
  • 5.15.0-1089.96
  • 5.15.0-1090.97
  • 5.15.0-1091.98
  • 5.15.0-1092.99
  • 5.15.0-1093.100
  • 5.15.0-1095.102
  • 5.15.0-1096.103
  • 5.15.0-1097.104
  • 5.15.0-1098.105
  • 5.15.0-1099.106
  • 5.15.0-1100.107
  • 5.15.0-1101.108
  • 5.15.0-1103.110
  • 5.15.0-1104.111
  • 5.15.0-1105.112
  • 5.15.0-1106.113
  • 5.15.0-1108.115
  • 5.15.0-1109.116
  • 5.15.0-1111.118
Ubuntu 22.04 Azure Released
78 kernels
  • 5.15.0-1005.6
  • 5.15.0-1007.8
  • 5.15.0-1010.12
  • 5.15.0-1012.15
  • 5.15.0-1014.17
  • 5.15.0-1017.20
  • 5.15.0-1008.9
  • 5.15.0-1019.24
  • 5.15.0-1020.25
  • 5.15.0-1021.26
  • 5.15.0-1022.27
  • 5.15.0-1003.4
  • 5.15.0-1013.16
  • 5.15.0-1023.29
  • 5.15.0-1029.36
  • 5.15.0-1024.30
  • 5.15.0-1034.41
  • 5.15.0-1035.42
  • 5.15.0-1036.43
  • 5.15.0-1037.44
  • 5.15.0-1038.45
  • 5.15.0-1039.46
  • 5.15.0-1040.47
  • 5.15.0-1041.48
  • 5.15.0-1042.49
  • 5.15.0-1045.52
  • 5.15.0-1046.53
  • 5.15.0-1047.54
  • 5.15.0-1049.56
  • 5.15.0-1044.51
  • 5.15.0-1050.57
  • 5.15.0-1051.59
  • 5.15.0-1052.60
  • 5.15.0-1053.61
  • 5.15.0-1054.62
  • 5.15.0-1056.64
  • 5.15.0-1057.65
  • 5.15.0-1058.66
  • 5.15.0-1059.67
  • 5.15.0-1060.69
  • 5.15.0-1061.70
  • 5.15.0-1063.72
  • 5.15.0-1064.73
  • 5.15.0-1066.75
  • 5.15.0-1067.76
  • 5.15.0-1068.77
  • 5.15.0-1070.79
  • 5.15.0-1071.80
  • 5.15.0-1072.81
  • 5.15.0-1073.82
  • 5.15.0-1074.83
  • 5.15.0-1075.84
  • 5.15.0-1078.87
  • 5.15.0-1079.88
  • 5.15.0-1081.90
  • 5.15.0-1082.91
  • 5.15.0-1084.93
  • 5.15.0-1086.95
  • 5.15.0-1087.96
  • 5.15.0-1088.97
  • 5.15.0-1089.98
  • 5.15.0-1090.99
  • 5.15.0-1091.100
  • 5.15.0-1092.101
  • 5.15.0-1094.103
  • 5.15.0-1095.104
  • 5.15.0-1096.105
  • 5.15.0-1097.106
  • 5.15.0-1098.107
  • 5.15.0-1101.110
  • 5.15.0-1102.111
  • 5.15.0-1099.108
  • 5.15.0-1103.112
  • 5.15.0-1109.118
  • 5.15.0-1110.119
  • 5.15.0-1111.120
  • 5.15.0-1114.123
  • 5.15.0-1116.125
Ubuntu 24.04 Released
46 kernels
  • 6.8.0-35.35
  • 6.8.0-38.38
  • 6.8.0-36.36
  • 6.8.0-39.39
  • 6.8.0-40.40
  • 6.8.0-41.41
  • 6.8.0-44.44
  • 6.8.0-45.45
  • 6.8.0-31.31
  • 6.8.0-47.47
  • 6.8.0-48.48
  • 6.8.0-49.49
  • 6.8.0-50.51
  • 6.8.0-51.52
  • 6.8.0-52.53
  • 6.8.0-54.56
  • 6.8.0-55.57
  • 6.8.0-53.55
  • 6.8.0-56.58
  • 6.8.0-57.59
  • 6.8.0-58.60
  • 6.8.0-59.61
  • 6.8.0-60.63
  • 6.8.0-62.65
  • 6.8.0-63.66
  • 6.8.0-64.67
  • 6.8.0-71.71
  • 6.8.0-78.78
  • 6.8.0-79.79
  • 6.8.0-84.84
  • 6.8.0-85.85
  • 6.8.0-83.83
  • 6.8.0-86.87
  • 6.8.0-87.88
  • 6.8.0-88.89
  • 6.8.0-90.91
  • 6.8.0-94.96
  • 6.8.0-100.100
  • 6.8.0-101.101
  • 6.8.0-106.106
  • 6.8.0-107.107
  • 6.8.0-110.110
  • 6.8.0-111.111
  • 6.8.0-117.117
  • 6.8.0-124.124
  • 6.8.0-134.134