🛡️ CVE-2023-53477 on Ubuntu — linux
Description
In the Linux kernel, the following vulnerability has been resolved: ipv6: Add lwtunnel encap size of all siblings in nexthop calculation In function rt6_nlmsg_size(), the length of nexthop is calculated by multipling the nexthop length of fib6_info and the number of siblings. However if the fib6_info has no lwtunnel but the siblings have lwtunnels, the nexthop length is less than it should be, and it will trigger a warning in inet6_rt_notify() as follows: WARNING: CPU: 0 PID: 6082 at net/ipv6/route.c:6180 inet6_rt_notify+0x120/0x130 ...... Call Trace: <TASK> fib6_add_rt2node+0x685/0xa30 fib6_add+0x96/0x1b0 ip6_route_add+0x50/0xd0 inet6_rtm_newroute+0x97/0xa0 rtnetlink_rcv_msg+0x156/0x3d0 netlink_rcv_skb+0x5a/0x110 netlink_unicast+0x246/0x350 netlink_sendmsg+0x250/0x4c0 sock_sendmsg+0x66/0x70 ___sys_sendmsg+0x7c/0xd0 __sys_sendmsg+0x5d/0xb0 do_syscall_64+0x3f/0x90 entry_SYSCALL_64_after_hwframe+0x72/0xdc This bug can be reproduced by script: ip -6 addr add 2002::2/64 dev ens2 ip -6 route add 100::/64 via 2002::1 dev ens2 metric 100 for i in 10 20 30 40 50 60 70; do ip link add link ens2 name ipv_$i type ipvlan ip -6 addr add 2002::$i/64 dev ipv_$i ifconfig ipv_$i up done for i in 10 20 30 40 50 60; do ip -6 route append 100::/64 encap ip6 dst 2002::$i via 2002::1 dev ipv_$i metric 100 done ip -6 route append 100::/64 via 2002::1 dev ipv_70 metric 100 This patch fixes it by adding nexthop_len of every siblings using rt6_nh_nlmsg_size().
Distribution advisory
This page covers CVE-2023-53477 as tracked by Ubuntu, for the package linux. The fix is available in version 5.15.0-79.86; earlier versions remain affected.
How this vulnerability can be exploited
This issue can be reached with local access to the system, attack complexity is low, an attacker needs low-level privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity none, availability high.
CVSS metrics in full
The score comes from this vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- Attack vector: Local — a local account, shell or session on the host is needed.
- Attack complexity: Low — the attack works reliably, with no preparation.
- Privileges required: Low — an ordinary user account is enough.
- User interaction: None — nobody has to be tricked into anything.
- Scope: Unchanged — the damage stays inside the vulnerable component.
- Confidentiality impact: None.
- Integrity impact: None.
- Availability impact: High — total loss, or loss the attacker controls.
Affected software
UBUNTU-CVE-2023-53477 is recorded against 122 packages.
- linux (fixed in 5.15.0-79.86)
- linux-allwinner-5.19
- linux-aws (fixed in 5.15.0-1042.47)
- linux-aws-5.0
- linux-aws-5.11
- linux-aws-5.13
- linux-aws-5.15 (fixed in 5.15.0-1041.46~20.04.1)
- linux-aws-5.19
- linux-aws-5.3
- linux-aws-5.4 (fixed in 5.4.0-1104.112~18.04.1)
- linux-aws-5.8
- linux-aws-6.2
- linux-aws-6.5
- linux-aws-fips
- linux-aws-hwe
- linux-azure (fixed in 5.15.0-1045.52)
- linux-azure-4.15
- linux-azure-5.11
- linux-azure-5.13
- linux-azure-5.15 (fixed in 5.15.0-1045.52~20.04.1)
- linux-azure-5.19
- linux-azure-5.3
- linux-azure-5.4 (fixed in 5.4.0-1110.116~18.04.1)
- linux-azure-5.8
Show the remaining 98 packages
- linux-azure-6.11
- linux-azure-6.2
- linux-azure-6.5
- linux-azure-edge
- linux-azure-fde
- linux-azure-fde-5.19
- linux-azure-fde-6.2
- linux-azure-fips
- linux-bluefield
- linux-fips
- linux-gcp (fixed in 5.15.0-1039.47)
- linux-gcp-4.15
- linux-gcp-5.11
- linux-gcp-5.13
- linux-gcp-5.15 (fixed in 5.15.0-1039.47~20.04.1)
- linux-gcp-5.19
- linux-gcp-5.3
- linux-gcp-5.4 (fixed in 5.4.0-1107.116~18.04.1)
- linux-gcp-5.8
- linux-gcp-6.11
- linux-gcp-6.2
- linux-gcp-6.5
- linux-gcp-fips
- linux-gke (fixed in 5.15.0-1039.44)
- linux-gke-4.15
- linux-gke-5.15
- linux-gke-5.4
- linux-gkeop (fixed in 5.15.0-1025.30)
- linux-gkeop-5.15
- linux-gkeop-5.4
- linux-hwe
- linux-hwe-5.11
- linux-hwe-5.13
- linux-hwe-5.15 (fixed in 5.15.0-79.86~20.04.2)
- linux-hwe-5.19
- linux-hwe-5.4 (fixed in 5.4.0-152.169~18.04.1)
- linux-hwe-5.8
- linux-hwe-6.11
- linux-hwe-6.2
- linux-hwe-6.5
- linux-hwe-edge
- linux-ibm (fixed in 5.15.0-1035.38)
- linux-ibm-5.15 (fixed in 5.15.0-1036.39~20.04.1)
- linux-ibm-5.4 (fixed in 5.4.0-1051.56~18.04.1)
- linux-intel
- linux-intel-5.13
- linux-intel-iot-realtime (fixed in 5.15.0-1036.38)
- linux-intel-iotg (fixed in 5.15.0-1037.42)
- linux-intel-iotg-5.15 (fixed in 5.15.0-1037.42~20.04.1)
- linux-iot (fixed in 5.4.0-1017.18)
- linux-kvm (fixed in 5.15.0-1039.44)
- linux-lowlatency (fixed in 5.15.0-79.88)
- linux-lowlatency-hwe-5.15 (fixed in 5.15.0-79.88~20.04.1)
- linux-lowlatency-hwe-5.19
- linux-lowlatency-hwe-6.11
- linux-lowlatency-hwe-6.2
- linux-lowlatency-hwe-6.5
- linux-nvidia (fixed in 5.15.0-1030.30)
- linux-nvidia-6.2
- linux-nvidia-6.5
- linux-nvidia-tegra (fixed in 5.15.0-1016.16)
- linux-nvidia-tegra-5.15 (fixed in 5.15.0-1016.16~20.04.1)
- linux-nvidia-tegra-igx (fixed in 5.15.0-1002.2)
- linux-oem
- linux-oem-5.10
- linux-oem-5.13
- linux-oem-5.14
- linux-oem-5.17
- linux-oem-5.6
- linux-oem-6.0
- linux-oem-6.1
- linux-oem-6.11
- linux-oem-6.5
- linux-oem-6.8
- linux-oracle (fixed in 5.15.0-1040.46)
- linux-oracle-5.0
- linux-oracle-5.11
- linux-oracle-5.13
- linux-oracle-5.15 (fixed in 5.15.0-1040.46~20.04.1)
- linux-oracle-5.3
- linux-oracle-5.4 (fixed in 5.4.0-1103.112~18.04.1)
- linux-oracle-5.8
- linux-oracle-6.5
- linux-raspi (fixed in 5.15.0-1035.38)
- linux-raspi-5.4 (fixed in 5.4.0-1088.99~18.04.1)
- linux-raspi-realtime
- linux-raspi2
- linux-realtime
- linux-riscv
- linux-riscv-5.11
- linux-riscv-5.15 (fixed in 5.15.0-1038.42~20.04.2)
- linux-riscv-5.19
- linux-riscv-5.8
- linux-riscv-6.5
- linux-starfive-5.19
- linux-starfive-6.2
- linux-starfive-6.5
- linux-xilinx-zynqmp (fixed in 5.15.0-1025.29)
Timeline and source
Published on 1 October 2025 and last revised on 19 August 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.
References
ubuntu.com (Report)
www.cve.org (Report)
git.kernel.org (Report)
git.kernel.org (Report)
git.kernel.org (Report)
git.kernel.org (Report)
git.kernel.org (Report)
git.kernel.org (Report)
git.kernel.org (Report)
Other advisories for this package
linux has other advisories on record. If you are patching this one, these are worth checking on the same host:
- DEBIAN-CVE-2022-4994 (published 30 Jul 2026)
- CVE-2026-21996 (3.3 Low, published 1 May 2026)
- CVE-2026-35233 (4.4 Medium, published 1 May 2026)
- CVE-2026-21991 (5.5 Medium, published 16 Mar 2026)
- CGA-mcwh-q4vm-9f29 (published 29 Jan 2026)
- CGA-w6xv-3fg4-grm5 (published 29 Jan 2026)
- CGA-6749-c84f-cv6j (published 7 Jan 2026)
- CGA-gqvj-m2xp-q99r (published 7 Jan 2026)
CVE-2023-53477 on other distributions
Each distribution ships its own build and its own fixed version. Pick the one you run:
Details
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Affected Packages
| Software | From version | Fixed in |
|---|---|---|
| linux | — | 5.15.0-79.86 |
| linux-allwinner-5.19 | — | — |
| linux-aws | — | 5.15.0-1042.47 |
| linux-aws-5.0 | — | — |
| linux-aws-5.11 | — | — |
| linux-aws-5.13 | — | — |
| linux-aws-5.15 | — | 5.15.0-1041.46~20.04.1 |
| linux-aws-5.19 | — | — |
| linux-aws-5.3 | — | — |
| linux-aws-5.4 | — | 5.4.0-1104.112~18.04.1 |
| linux-aws-5.8 | — | — |
| linux-aws-6.2 | — | — |
| linux-aws-6.5 | — | — |
| linux-aws-fips | — | — |
| linux-aws-hwe | — | — |
| linux-azure | — | 5.15.0-1045.52 |
| linux-azure-4.15 | — | — |
| linux-azure-5.11 | — | — |
| linux-azure-5.13 | — | — |
| linux-azure-5.15 | — | 5.15.0-1045.52~20.04.1 |
| linux-azure-5.19 | — | — |
| linux-azure-5.3 | — | — |
| linux-azure-5.4 | — | 5.4.0-1110.116~18.04.1 |
| linux-azure-5.8 | — | — |
| linux-azure-6.11 | — | — |
| linux-azure-6.2 | — | — |
| linux-azure-6.5 | — | — |
| linux-azure-edge | — | — |
| linux-azure-fde | — | — |
| linux-azure-fde-5.19 | — | — |
| linux-azure-fde-6.2 | — | — |
| linux-azure-fips | — | — |
| linux-bluefield | — | — |
| linux-fips | — | — |
| linux-gcp | — | 5.15.0-1039.47 |
| linux-gcp-4.15 | — | — |
| linux-gcp-5.11 | — | — |
| linux-gcp-5.13 | — | — |
| linux-gcp-5.15 | — | 5.15.0-1039.47~20.04.1 |
| linux-gcp-5.19 | — | — |
| linux-gcp-5.3 | — | — |
| linux-gcp-5.4 | — | 5.4.0-1107.116~18.04.1 |
| linux-gcp-5.8 | — | — |
| linux-gcp-6.11 | — | — |
| linux-gcp-6.2 | — | — |
| linux-gcp-6.5 | — | — |
| linux-gcp-fips | — | — |
| linux-gke | — | 5.15.0-1039.44 |
| linux-gke-4.15 | — | — |
| linux-gke-5.15 | — | — |
| linux-gke-5.4 | — | — |
| linux-gkeop | — | 5.15.0-1025.30 |
| linux-gkeop-5.15 | — | — |
| linux-gkeop-5.4 | — | — |
| linux-hwe | — | — |
| linux-hwe-5.11 | — | — |
| linux-hwe-5.13 | — | — |
| linux-hwe-5.15 | — | 5.15.0-79.86~20.04.2 |
| linux-hwe-5.19 | — | — |
| linux-hwe-5.4 | — | 5.4.0-152.169~18.04.1 |
| linux-hwe-5.8 | — | — |
| linux-hwe-6.11 | — | — |
| linux-hwe-6.2 | — | — |
| linux-hwe-6.5 | — | — |
| linux-hwe-edge | — | — |
| linux-ibm | — | 5.15.0-1035.38 |
| linux-ibm-5.15 | — | 5.15.0-1036.39~20.04.1 |
| linux-ibm-5.4 | — | 5.4.0-1051.56~18.04.1 |
| linux-intel | — | — |
| linux-intel-5.13 | — | — |
| linux-intel-iot-realtime | — | 5.15.0-1036.38 |
| linux-intel-iotg | — | 5.15.0-1037.42 |
| linux-intel-iotg-5.15 | — | 5.15.0-1037.42~20.04.1 |
| linux-iot | — | 5.4.0-1017.18 |
| linux-kvm | — | 5.15.0-1039.44 |
| linux-lowlatency | — | 5.15.0-79.88 |
| linux-lowlatency-hwe-5.15 | — | 5.15.0-79.88~20.04.1 |
| linux-lowlatency-hwe-5.19 | — | — |
| linux-lowlatency-hwe-6.11 | — | — |
| linux-lowlatency-hwe-6.2 | — | — |
| linux-lowlatency-hwe-6.5 | — | — |
| linux-nvidia | — | 5.15.0-1030.30 |
| linux-nvidia-6.2 | — | — |
| linux-nvidia-6.5 | — | — |
| linux-nvidia-tegra | — | 5.15.0-1016.16 |
| linux-nvidia-tegra-5.15 | — | 5.15.0-1016.16~20.04.1 |
| linux-nvidia-tegra-igx | — | 5.15.0-1002.2 |
| linux-oem | — | — |
| linux-oem-5.10 | — | — |
| linux-oem-5.13 | — | — |
| linux-oem-5.14 | — | — |
| linux-oem-5.17 | — | — |
| linux-oem-5.6 | — | — |
| linux-oem-6.0 | — | — |
| linux-oem-6.1 | — | — |
| linux-oem-6.11 | — | — |
| linux-oem-6.5 | — | — |
| linux-oem-6.8 | — | — |
| linux-oracle | — | 5.15.0-1040.46 |
| linux-oracle-5.0 | — | — |
| linux-oracle-5.11 | — | — |
| linux-oracle-5.13 | — | — |
| linux-oracle-5.15 | — | 5.15.0-1040.46~20.04.1 |
| linux-oracle-5.3 | — | — |
| linux-oracle-5.4 | — | 5.4.0-1103.112~18.04.1 |
| linux-oracle-5.8 | — | — |
| linux-oracle-6.5 | — | — |
| linux-raspi | — | 5.15.0-1035.38 |
| linux-raspi-5.4 | — | 5.4.0-1088.99~18.04.1 |
| linux-raspi-realtime | — | — |
| linux-raspi2 | — | — |
| linux-realtime | — | — |
| linux-riscv | — | — |
| linux-riscv-5.11 | — | — |
| linux-riscv-5.15 | — | 5.15.0-1038.42~20.04.2 |
| linux-riscv-5.19 | — | — |
| linux-riscv-5.8 | — | — |
| linux-riscv-6.5 | — | — |
| linux-starfive-5.19 | — | — |
| linux-starfive-6.2 | — | — |
| linux-starfive-6.5 | — | — |
| linux-xilinx-zynqmp | — | 5.15.0-1025.29 |
References
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