# CVE-2024-26882: net: ip_tunnel: make sure to pull inner header in ip_tunnel_rcv() > A missing header pull in the Linux kernel IP tunnel receive path allows attackers to read uninitialized kernel memory via crafted packets. - **Severity:** High 7.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 17 Apr 2024 - **Updated:** 15 Oct 2026 - **Also known as:** AZL-40168, BELL-CVE-2024-26882, DEBIAN-CVE-2024-26882, GHSA-mhpf-x66q-8p92, UBUNTU-CVE-2024-26882, USN-6925-1 ## What is CVE-2024-26882? CVE-2024-26882 is a high-severity vulnerability in Linux kernel, published on 17 Apr 2024. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description In the Linux kernel, the following vulnerability has been resolved: net: ip_tunnel: make sure to pull inner header in ip_tunnel_rcv() Apply the same fix than ones found in : 8d975c15c0cd ("ip6_tunnel: make sure to pull inner header in __ip6_tnl_rcv()") 1ca1ba465e55 ("geneve: make sure to pull inner header in geneve_rx()") We have to save skb->network_header in a temporary variable in order to be able to recompute the network_header pointer after a pskb_inet_may_pull() call. pskb_inet_may_pull() makes sure the needed headers are in skb->head. syzbot reported: 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 IP_ECN_decapsulate include/net/inet_ecn.h:302 [inline] BUG: KMSAN: uninit-value in ip_tunnel_rcv+0xed9/0x2ed0 net/ipv4/ip_tunnel.c:409 __INET_ECN_decapsulate include/net/inet_ecn.h:253 [inline] INET_ECN_decapsulate include/net/inet_ecn.h:275 [inline] IP_ECN_decapsulate include/net/inet_ecn.h:302 [inline] ip_tunnel_rcv+0xed9/0x2ed0 net/ipv4/ip_tunnel.c:409 __ipgre_rcv+0x9bc/0xbc0 net/ipv4/ip_gre.c:389 ipgre_rcv net/ipv4/ip_gre.c:411 [inline] gre_rcv+0x423/0x19f0 net/ipv4/ip_gre.c:447 gre_rcv+0x2a4/0x390 net/ipv4/gre_demux.c:163 ip_protocol_deliver_rcu+0x264/0x1300 net/ipv4/ip_input.c:205 ip_local_deliver_finish+0x2b8/0x440 net/ipv4/ip_input.c:233 NF_HOOK include/linux/netfilter.h:314 [inline] ip_local_deliver+0x21f/0x490 net/ipv4/ip_input.c:254 dst_input include/net/dst.h:461 [inline] ip_rcv_finish net/ipv4/ip_input.c:449 [inline] NF_HOOK include/linux/netfilter.h:314 [inline] ip_rcv+0x46f/0x760 net/ipv4/ip_input.c:569 __netif_receive_skb_one_core net/core/dev.c:5534 [inline] __netif_receive_skb+0x1a6/0x5a0 net/core/dev.c:5648 netif_receive_skb_internal net/core/dev.c:5734 [inline] netif_receive_skb+0x58/0x660 net/core/dev.c:5793 tun_rx_batched+0x3ee/0x980 drivers/net/tun.c:1556 tun_get_user+0x53b9/0x66e0 drivers/net/tun.c:2009 tun_chr_write_iter+0x3af/0x5d0 drivers/net/tun.c:2055 call_write_iter include/linux/fs.h:2087 [inline] new_sync_write fs/read_write.c:497 [inline] vfs_write+0xb6b/0x1520 fs/read_write.c:590 ksys_write+0x20f/0x4c0 fs/read_write.c:643 __do_sys_write fs/read_write.c:655 [inline] __se_sys_write fs/read_write.c:652 [inline] __x64_sys_write+0x93/0xd0 fs/read_write.c:652 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x63/0x6b Uninit was created at: __alloc_pages+0x9a6/0xe00 mm/page_alloc.c:4590 alloc_pages_mpol+0x62b/0x9d0 mm/mempolicy.c:2133 alloc_pages+0x1be/0x1e0 mm/mempolicy.c:2204 skb_page_frag_refill+0x2bf/0x7c0 net/core/sock.c:2909 tun_build_skb drivers/net/tun.c:1686 [inline] tun_get_user+0xe0a/0x66e0 drivers/net/tun.c:1826 tun_chr_write_iter+0x3af/0x5d0 drivers/net/tun.c:2055 call_write_iter include/linux/fs.h:2087 [inline] new_sync_write fs/read_write.c:497 [inline] vfs_write+0xb6b/0x1520 fs/read_write.c:590 ksys_write+0x20f/0x4c0 fs/read_write.c:643 __do_sys_write fs/read_write.c:655 [inline] __se_sys_write fs/read_write.c:652 [inline] __x64_sys_write+0x93/0xd0 fs/read_write.c:652 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x63/0x6b Weakness: CWE-457 (Use of Uninitialized Variable) ## Which versions are affected by CVE-2024-26882? It affects 1 product. Products: Linux kernel. ## How do I fix CVE-2024-26882? Apply the vendor's patch. ## Is CVE-2024-26882 being exploited? There is no known exploitation of CVE-2024-26882 in the wild and no public exploit code. ## Other vulnerabilities in Linux kernel - [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild) - [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild) - [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild) - [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild) - [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2024-26882 and fix it if it is affected. What it is: CVE-2024-26882 is a high-severity vulnerability in Linux kernel, published on 17 Apr 2024. An attacker can exploit it over the internet without logging in, with no action from the victim. Exploitation: There is no known exploitation of CVE-2024-26882 in the wild and no public exploit code. Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page. Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2024-26882/ (Markdown: https://insights.sbomify.com/CVE-2024-26882/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2024-26882 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-26882 - OSV: https://osv.dev/vulnerability/CVE-2024-26882 --- From sbomify Insights: https://insights.sbomify.com/CVE-2024-26882/ Summaries are generated and may contain mistakes; the official description above is the record.