Linux Kernel up to 7.1.2 ipv6 __ip6_append_data end allocation of resources

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.1.176/6.6.143/6.12.94/6.18.37/7.1.2 and classified as critical. This vulnerability affects the function __ip6_append_data of the component ipv6. Executing a manipulation of the argument end can lead to allocation of resources. The identification of this vulnerability is CVE-2026-53362. There is no exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.1.176/6.6.143/6.12.94/6.18.37/7.1.2. It has been declared as critical. This vulnerability affects the function __ip6_append_data of the component ipv6. The manipulation of the argument end with an unknown input leads to a allocation of resources vulnerability. The CWE definition for the vulnerability is CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. As an impact it is known to affect availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: ipv6: account for fraggap on the paged allocation path In __ip6_append_data(), when the paged-allocation branch is taken (MSG_MORE / NETIF_F_SG / large fraglen), alloclen and pagedlen are computed as alloclen = fragheaderlen + transhdrlen; pagedlen = datalen - transhdrlen; datalen already includes fraggap (datalen = length + fraggap). When fraggap is non-zero, this is not the first skb and transhdrlen is zero. The fraggap bytes carried over from the previous skb are copied just past the fragment headers in the new skb's linear area. The linear area is therefore undersized by fraggap bytes while pagedlen is overstated by the same amount, and the copy writes past skb->end into the trailing skb_shared_info. An unprivileged user can trigger this via a UDPv6 socket using MSG_MORE together with MSG_SPLICE_PAGES. The bad accounting was introduced by commit 773ba4fe9104 ("ipv6: avoid partial copy for zc"). Before commit ce650a166335 ("udp6: Fix __ip6_append_data()'s handling of MSG_SPLICE_PAGES"), the negative copy value caused -EINVAL to be returned. That later commit allowed MSG_SPLICE_PAGES to proceed in this case, making the corruption triggerable. The non-paged branch sets alloclen to fraglen, which already accounts for fraggap because datalen does. Bring the paged branch in line by adding fraggap to alloclen and subtracting it from pagedlen. After this adjustment, copy no longer collapses to -fraggap on the paged path, so remove the stale comment describing that old arithmetic. Since a negative copy is no longer expected for a valid MSG_SPLICE_PAGES case, remove the MSG_SPLICE_PAGES exception from the negative copy check.

The advisory is shared for download at git.kernel.org. This vulnerability was named CVE-2026-53362 since 06/09/2026. The exploitation appears to be easy. There are known technical details, but no exploit is available.

Upgrading to version 6.1.177, 6.6.144, 6.12.95, 6.18.38, 7.1.3 or 7.2-rc1 eliminates this vulnerability. Applying the patch 14200d435af9a9eeb444f529fc2f689a236b7962/65fb14cbebb0cd0eff903a22d33537ddc8b95769/46f201f8b4c39633a1fa3dc12459f506d470993d/6374fb9edf72c67a118a2c214a0dddd04c921e0a/e9eacf19281ea2498b36291b56c9606118c2d74e/736b380e28d0480c7bc3e022f1950f31fe53a7c5 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.1.176
• 6.6.143
• 6.12.0
• 6.12.1
• 6.12.2
• 6.12.3
• 6.12.4
• 6.12.5
• 6.12.6
• 6.12.7
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• 6.12.36
• 6.12.37
• 6.12.38
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• 6.12.80
• 6.12.81
• 6.12.82
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• 6.12.84
• 6.12.85
• 6.12.86
• 6.12.87
• 6.12.88
• 6.12.89
• 6.12.90
• 6.12.91
• 6.12.92
• 6.12.93
• 6.12.94
• 6.18.0
• 6.18.1
• 6.18.2
• 6.18.3
• 6.18.4
• 6.18.5
• 6.18.6
• 6.18.7
• 6.18.8
• 6.18.9
• 6.18.10
• 6.18.11
• 6.18.12
• 6.18.13
• 6.18.14
• 6.18.15
• 6.18.16
• 6.18.17
• 6.18.18
• 6.18.19
• 6.18.20
• 6.18.21
• 6.18.22
• 6.18.23
• 6.18.24
• 6.18.25
• 6.18.26
• 6.18.27
• 6.18.28
• 6.18.29
• 6.18.30
• 6.18.31
• 6.18.32
• 6.18.33
• 6.18.34
• 6.18.35
• 6.18.36
• 6.18.37
• 7.1.0
• 7.1.1
• 7.1.2

License

• open-source

Website

• Vendor: https://www.kernel.org/

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