CVE-2026-23003

MEDIUMNVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

Score 5.5 from GitHub Security Advisory published 2026-01-25. NVD baseline CVSS 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
5.5
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 5.5Exploit: NoneExposed: 0

A fix is available — apply it.

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

ip6_tunnel: use skb_vlan_inet_prepare() in __ip6_tnl_rcv()

Blamed commit did not take care of VLAN encapsulations as spotted by syzbot [1].

Use skb_vlan_inet_prepare() instead of pskb_inet_may_pull().

[1] BUG: KMSAN: uninit-value in __INET_ECN_decapsulate include/net/inet_ecn.h:253 [inline] BUG: KMSAN: uninit-value in INET_ECN_decapsulate include/net/inet_ecn.h:275 [inline] BUG: KMSAN: uninit-value in IP6_ECN_decapsulate+0x7a8/0x1fa0 include/net/inet_ecn.h:321 __INET_ECN_decapsulate include/net/inet_ecn.h:253 [inline] INET_ECN_decapsulate include/net/inet_ecn.h:275 [inline] IP6_ECN_decapsulate+0x7a8/0x1fa0 include/net/inet_ecn.h:321 ip6ip6_dscp_ecn_decapsulate+0x16f/0x1b0 net/ipv6/ip6_tunnel.c:729 __ip6_tnl_rcv+0xed9/0x1b50 net/ipv6/ip6_tunnel.c:860 ip6_tnl_rcv+0xc3/0x100 net/ipv6/ip6_tunnel.c:903 gre_rcv+0x1529/0x1b90 net/ipv6/ip6_gre.c:-1 ip6_protocol_deliver_rcu+0x1c89/0x2c60 net/ipv6/ip6_input.c:438 ip6_input_finish+0x1f4/0x4a0 net/ipv6/ip6_input.c:489 NF_HOOK include/linux/netfilter.h:318 [inline] ip6_input+0x9c/0x330 net/ipv6/ip6_input.c:500 ip6_mc_input+0x7ca/0xc10 net/ipv6/ip6_input.c:590 dst_input include/net/dst.h:474 [inline] ip6_rcv_finish+0x958/0x990 net/ipv6/ip6_input.c:79 NF_HOOK include/linux/netfilter.h:318 [inline] ipv6_rcv+0xf1/0x3c0 net/ipv6/ip6_input.c:311 __netif_receive_skb_one_core net/core/dev.c:6139 [inline] __netif_receive_skb+0x1df/0xac0 net/core/dev.c:6252 netif_receive_skb_internal net/core/dev.c:6338 [inline] netif_receive_skb+0x57/0x630 net/core/dev.c:6397 tun_rx_batched+0x1df/0x980 drivers/net/tun.c:1485 tun_get_user+0x5c0e/0x6c60 drivers/net/tun.c:1953 tun_chr_write_iter+0x3e9/0x5c0 drivers/net/tun.c:1999 new_sync_write fs/read_write.c:593 [inline] vfs_write+0xbe2/0x15d0 fs/read_write.c:686 ksys_write fs/read_write.c:738 [inline] __do_sys_write fs/read_write.c:749 [inline] __se_sys_write fs/read_write.c:746 [inline] __x64_sys_write+0x1fb/0x4d0 fs/read_write.c:746 x64_sys_call+0x30ab/0x3e70 arch/x86/include/generated/asm/syscalls_64.h:2 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd3/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at: slab_post_alloc_hook mm/slub.c:4960 [inline] slab_alloc_node mm/slub.c:5263 [inline] kmem_cache_alloc_node_noprof+0x9e7/0x17a0 mm/slub.c:5315 kmalloc_reserve+0x13c/0x4b0 net/core/skbuff.c:586 __alloc_skb+0x805/0x1040 net/core/skbuff.c:690 alloc_skb include/linux/skbuff.h:1383 [inline] alloc_skb_with_frags+0xc5/0xa60 net/core/skbuff.c:6712 sock_alloc_send_pskb+0xacc/0xc60 net/core/sock.c:2995 tun_alloc_skb drivers/net/tun.c:1461 [inline] tun_get_user+0x1142/0x6c60 drivers/net/tun.c:1794 tun_chr_write_iter+0x3e9/0x5c0 drivers/net/tun.c:1999 new_sync_write fs/read_write.c:593 [inline] vfs_write+0xbe2/0x15d0 fs/read_write.c:686 ksys_write fs/read_write.c:738 [inline] __do_sys_write fs/read_write.c:749 [inline] __se_sys_write fs/read_write.c:746 [inline] __x64_sys_write+0x1fb/0x4d0 fs/read_write.c:746 x64_sys_call+0x30ab/0x3e70 arch/x86/include/generated/asm/syscalls_64.h:2 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd3/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 0 UID: 0 PID: 6465 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(none) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025

CVSS v3
5.5
EG Score
5.5(medium)
EG Risk
40(Track)
EG Risk 40/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity55% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
37.9%
KEV
Not listed

Published

January 25, 2026

Last Modified

July 14, 2026

Advisory Details (8)

Auto-updated Jul 14, 2026
No patch confirmed yet.
generic

SSA-019113

https://cert-portal.siemens.com/productcert/html/ssa-019113.html
generic

ip6_tunnel: use skb_vlan_inet_prepare() in __ip6_tnl_rcv() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/f9c5c5b791d3850570796f9e067629474e613796
generic

ip6_tunnel: use skb_vlan_inet_prepare() in __ip6_tnl_rcv() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/df5ffde9669314500809bc498ae73d6d3d9519ac
generic

ip6_tunnel: use skb_vlan_inet_prepare() in __ip6_tnl_rcv() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/b9f915340f25cae1562f18e1eb52deafca328414
generic

ip6_tunnel: use skb_vlan_inet_prepare() in __ip6_tnl_rcv() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/9e1c8c2a33d0a7b1f637b5d0602fe56ed10166af
generic

ip6_tunnel: use skb_vlan_inet_prepare() in __ip6_tnl_rcv() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/81c734dae203757fb3c9eee6f9896386940776bd
generic

ip6_tunnel: use skb_vlan_inet_prepare() in __ip6_tnl_rcv() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/64c71d60a21a9ed0a802483dcd422b5b24eb1abe
generic

ip6_tunnel: use skb_vlan_inet_prepare() in __ip6_tnl_rcv() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/2f03dafea0a8096a2eb60f551218b360e5bab9a3

Vendor Advisories for CVE-2026-23003(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(21)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulinux-virtual-hwe-20.04-edge (5.15.0.176.161) @ jammy2026-06-08ubuntu
ubuntulinux-tools-nvidia-tegra-rt-5.15 (5.15.0.1057.57~20.04.1) @ focal2026-06-08ubuntu
ubuntulinux-virtual-hwe-20.04-edge (5.15.0.176.186~20.04.1) @ focal2026-06-08ubuntu
ubuntulinux-tools-azure-edge (5.15.0.1110.119~20.04.1) @ focal2026-06-08ubuntu
ubuntulinux-xilinx-zynqmp-tools-5.15.0-1070 (5.15.0-1070.74) @ jammy2026-06-08ubuntu
ubuntulinux-tools-raspi-nolpae (5.15.0.1099.97) @ jammy2026-06-08ubuntu
ubuntulinux-tools-ibm-5.15 (5.15.0.1099.95) @ jammy2026-06-08ubuntu
ubuntulinux-tools-azure-fips-5.15 (5.15.0.1110.95) @ jammy2026-06-08ubuntu
ubuntulinux-tools-nvidia-lowlatency-64k-6.8 (6.8.0-1054.57.1) @ noble2026-06-08ubuntu
ubuntulinux-tools-azure-lts-24.04 (6.8.0-1056.62) @ noble2026-06-08ubuntu
ubuntulinux-tools-azure-fips-6.8 (6.8.0-1059.65+fips1) @ noble2026-06-08ubuntu
ubuntulinux-tools-gcp-edge (5.15.0.1106.115~20.04.1) @ focal2026-06-08ubuntu
ubuntulinux-tools-realtime-5.15 (5.15.0.1104.108) @ jammy2026-06-08ubuntu
ubuntulinux-virtual-6.8 (6.8.0-117.117) @ noble2026-06-08ubuntu
ubuntulinux-tools-gcp-fips-5.15 (5.15.0.1105.95) @ jammy2026-06-08ubuntu
ubuntulinux-tools-nvidia-tegra-rt-6.8 (6.8.0-1024.24) @ noble2026-06-08ubuntu
ubuntulinux-tools-kvm-5.15 (5.15.0.1097.93) @ jammy2026-06-08ubuntu
ubuntulinux-tools-fips-6.8 (6.8.0-116.116+fips1) @ noble2026-06-08ubuntu
ubuntulinux-tools-nvidia-tegra-rt-5.15 (5.15.0.1057.57) @ jammy2026-06-08ubuntu
ubuntulinux-tools-nvidia-hwe-22.04-edge (6.8.0-1054.57~22.04.1) @ jammy2026-06-08ubuntu
linuxKernel @ 5.10.249—osv

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

All Vendor Advisories

(20)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 14× in last 7d / 52× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 126 total refreshes for this CVE.

  1. 2026-07-24 14:17 UTCEPSS rescore
  2. 2026-07-23 14:18 UTCEPSS rescore
  3. 2026-07-23 14:18 UTCEPSS rescore
  4. 2026-07-23 03:06 UTCEG score recompute
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  21. 2026-07-14 13:19 UTCNVD updateCVSS v3 → 5.5 · severity → MEDIUM
  22. 2026-07-13 22:30 UTCEPSS rescore
  23. 2026-07-13 15:07 UTCOSV refresh
  24. 2026-07-13 06:13 UTCEPSS rescore
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  1. 2026-07-12 05:46 UTCEPSS rescore
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  25. 2026-06-25 13:49 UTCEPSS rescore
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  27. 2026-06-25 12:31 UTCOSV refresh
  28. 2026-06-24 14:05 UTCEPSS rescore
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  30. 2026-06-23 21:33 UTCEPSS rescore
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  53. 2026-06-08 03:05 UTCVendor advisory
  54. 2026-06-08 03:05 UTCGHSA enrichment
  55. 2026-06-07 15:25 UTCEPSS rescore
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  68. 2026-06-01 16:27 UTCOSV refresh
  69. 2026-06-01 13:51 UTCEPSS rescore
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  74. 2026-05-31 00:16 UTCEPSS rescore
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Related CVEs(same product + same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-23003?
CVE-2026-23003 is a medium vulnerability published on January 25, 2026. In the Linux kernel, the following vulnerability has been resolved: ip6tunnel: use skbvlaninetprepare() in ip6tnlrcv() Blamed commit did not take care of VLAN encapsulations as spotted by syzbot [1]. Use skbvlaninetprepare() instead of pskbinetmaypull(). [1] BUG: KMSAN: uninit-value in…
When was CVE-2026-23003 disclosed?
CVE-2026-23003 was first published in the National Vulnerability Database on January 25, 2026, with the most recent update on July 14, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-23003 actively exploited?
CVE-2026-23003 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 37.9% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-23003?
CVE-2026-23003 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2026-23003?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-23003, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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