Linux Kernel up to 5.18.3 ip_gre buffer overflow

Summaryinfo

A vulnerability was found in Linux Kernel up to 5.18.3. It has been declared as critical. This vulnerability affects unknown code of the component ip_gre. The manipulation results in buffer overflow. This vulnerability is cataloged as CVE-2022-49340. There is no exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, was found in Linux Kernel up to 5.18.3. Affected is some unknown processing of the component ip_gre. The manipulation with an unknown input leads to a buffer overflow vulnerability. CWE is classifying the issue as CWE-120. The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: ip_gre: test csum_start instead of transport header GRE with TUNNEL_CSUM will apply local checksum offload on CHECKSUM_PARTIAL packets. ipgre_xmit must validate csum_start after an optional skb_pull, else lco_csum may trigger an overflow. The original check was if (csum && skb_checksum_start(skb) data) return -EINVAL; This had false positives when skb_checksum_start is undefined: when ip_summed is not CHECKSUM_PARTIAL. A discussed refinement was straightforward if (csum && skb->ip_summed == CHECKSUM_PARTIAL && skb_checksum_start(skb) data) return -EINVAL; But was eventually revised more thoroughly: - restrict the check to the only branch where needed, in an uncommon GRE path that uses header_ops and calls skb_pull. - test skb_transport_header, which is set along with csum_start in skb_partial_csum_set in the normal header_ops datapath. Turns out skbs can arrive in this branch without the transport header set, e.g., through BPF redirection. Revise the check back to check csum_start directly, and only if CHECKSUM_PARTIAL. Do leave the check in the updated location. Check field regardless of whether TUNNEL_CSUM is configured.

The advisory is shared for download at git.kernel.org. This vulnerability is traded as CVE-2022-49340 since 02/26/2025. The exploitability is told to be difficult. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 10/25/2025).

The vulnerability scanner Nessus provides a plugin with the ID 271309 (EulerOS 2.0 SP13 : kernel (EulerOS-SA-2025-2264)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 4.19.247, 5.4.198, 5.10.122, 5.15.47, 5.17.15 or 5.18.4 eliminates this vulnerability. Applying the patch 7596bd7920985f7fc8579a92e48bc53ce4475b21/3d08bc3a5d9b2106f5c8bcf1adb73147824aa006/fbeb8dfa8b87ef259eef0c89e39b53962a3cf604/e6b6f98fc7605c06c0a3baa70f62c534d7b4ce58/0c92d813c7c9ca2212ecd879232e7d87362fce98/0ffa268724656633af5f37a38c212326d98ebe8c/8d21e9963bec1aad2280cdd034c8993033ef2948 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.

The vulnerability is also documented in the vulnerability database at Tenable (271309). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 4.19.246
• 5.4.197
• 5.10.121
• 5.15.0
• 5.15.1
• 5.15.2
• 5.15.3
• 5.15.4
• 5.15.5
• 5.15.6
• 5.15.7
• 5.15.8
• 5.15.9
• 5.15.10
• 5.15.11
• 5.15.12
• 5.15.13
• 5.15.14
• 5.15.15
• 5.15.16
• 5.15.17
• 5.15.18
• 5.15.19
• 5.15.20
• 5.15.21
• 5.15.22
• 5.15.23
• 5.15.24
• 5.15.25
• 5.15.26
• 5.15.27
• 5.15.28
• 5.15.29
• 5.15.30
• 5.15.31
• 5.15.32
• 5.15.33
• 5.15.34
• 5.15.35
• 5.15.36
• 5.15.37
• 5.15.38
• 5.15.39
• 5.15.40
• 5.15.41
• 5.15.42
• 5.15.43
• 5.15.44
• 5.15.45
• 5.15.46
• 5.17.0
• 5.17.1
• 5.17.2
• 5.17.3
• 5.17.4
• 5.17.5
• 5.17.6
• 5.17.7
• 5.17.8
• 5.17.9
• 5.17.10
• 5.17.11
• 5.17.12
• 5.17.13
• 5.17.14
• 5.18.0
• 5.18.1
• 5.18.2
• 5.18.3

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

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Entryinfo

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