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CVE-2026-43038— ipv6: icmp: clear skb2->cb[] in ip6_err_gen_icmpv6_unreach()

CVSS 9.8 · Critical EPSS 0.07% · P21
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I. Basic Information for CVE-2026-43038

Vulnerability Information
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Vulnerability Title
ipv6: icmp: clear skb2->cb[] in ip6_err_gen_icmpv6_unreach()
Source: NVD (National Vulnerability Database)
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: ipv6: icmp: clear skb2->cb[] in ip6_err_gen_icmpv6_unreach() Sashiko AI-review observed: In ip6_err_gen_icmpv6_unreach(), the skb is an outer IPv4 ICMP error packet where its cb contains an IPv4 inet_skb_parm. When skb is cloned into skb2 and passed to icmp6_send(), it uses IP6CB(skb2). IP6CB interprets the IPv4 inet_skb_parm as an inet6_skb_parm. The cipso offset in inet_skb_parm.opt directly overlaps with dsthao in inet6_skb_parm at offset 18. If an attacker sends a forged ICMPv4 error with a CIPSO IP option, dsthao would be a non-zero offset. Inside icmp6_send(), mip6_addr_swap() is called and uses ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO). This would scan the inner, attacker-controlled IPv6 packet starting at that offset, potentially returning a fake TLV without checking if the remaining packet length can hold the full 18-byte struct ipv6_destopt_hao. Could mip6_addr_swap() then perform a 16-byte swap that extends past the end of the packet data into skb_shared_info? Should the cb array also be cleared in ip6_err_gen_icmpv6_unreach() and ip6ip6_err() to prevent this? This patch implements the first suggestion. I am not sure if ip6ip6_err() needs to be changed. A separate patch would be better anyway.
Source: NVD (National Vulnerability Database)
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Source: NVD (National Vulnerability Database)
Vulnerability Type
N/A
Source: NVD (National Vulnerability Database)
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于ip6_err_gen_icmpv6_unreach函数未清除skb2的cb数组，导致IPv4 cb结构被错误解释为IPv6 cb结构，可能引发越界扫描。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

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Affected Products

VendorProductAffected VersionsCPESubscribe
LinuxLinux ca15a078bd907df5fc1c009477869c5cbde3b753 ~ c438ba010171b70bad22fc18b1d5bdc3627476e8 -
LinuxLinux 3.13 -

II. Public POCs for CVE-2026-43038

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III. Intelligence Information for CVE-2026-43038

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Same Patch Batch · Linux · 2026-05-01 · 146 CVEs total

CVE-2026-430119.8 CRITICALnet/x25: Fix potential double free of skb
CVE-2026-430379.8 CRITICALip6_tunnel: clear skb2->cb[] in ip4ip6_err()
CVE-2026-317059.8 CRITICALksmbd: fix out-of-bounds write in smb2_get_ea() EA alignment
CVE-2026-430399.8 CRITICALnet: ti: icssg-prueth: fix missing data copy and wrong recycle in ZC RX dispatch
CVE-2026-317189.8 CRITICALksmbd: fix use-after-free in __ksmbd_close_fd() via durable scavenger
CVE-2026-430188.8 HIGHBluetooth: hci_event: fix potential UAF in hci_le_remote_conn_param_req_evt
CVE-2026-317738.8 HIGHBluetooth: SMP: derive legacy responder STK authentication from MITM state
CVE-2026-317398.8 HIGHcrypto: tegra - Add missing CRYPTO_ALG_ASYNC
CVE-2026-317358.8 HIGHiommupt: Fix short gather if the unmap goes into a large mapping
CVE-2026-317178.8 HIGHksmbd: validate owner of durable handle on reconnect
CVE-2026-317068.8 HIGHksmbd: validate num_aces and harden ACE walk in smb_inherit_dacl()
CVE-2026-430488.8 HIGHHID: core: Mitigate potential OOB by removing bogus memset()
CVE-2026-317098.8 HIGHsmb: client: validate the whole DACL before rewriting it in cifsacl
CVE-2026-317128.3 HIGHksmbd: require minimum ACE size in smb_check_perm_dacl()
CVE-2026-317718.1 HIGHBluetooth: hci_event: move wake reason storage into validated event handlers
CVE-2026-317798.1 HIGHwifi: iwlwifi: mvm: fix potential out-of-bounds read in iwl_mvm_nd_match_info_handler()
CVE-2026-317088.1 HIGHsmb: client: fix OOB read in smb2_ioctl_query_info QUERY_INFO path
CVE-2026-430518.1 HIGHHID: wacom: fix out-of-bounds read in wacom_intuos_bt_irq
CVE-2026-317807.8 HIGHwifi: wilc1000: fix u8 overflow in SSID scan buffer size calculation
CVE-2026-317827.8 HIGHperf/x86: Fix potential bad container_of in intel_pmu_hw_config

Showing top 20 of 146 CVEs. View all on vendor page → →

IV. Related Vulnerabilities

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Same vendor: Linux

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