Linux Kernel up to 6.12.48/6.16.8 ice_put_rx_mbuf buffer overflow

Summaryinfo

A vulnerability classified as critical has been found in Linux Kernel up to 6.12.48/6.16.8. This impacts the function ice_put_rx_mbuf. Performing a manipulation results in buffer overflow. This vulnerability is cataloged as CVE-2025-39948. There is no exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.12.48/6.16.8. It has been classified as critical. This affects the function ice_put_rx_mbuf. 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. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: ice: fix Rx page leak on multi-buffer frames The ice_put_rx_mbuf() function handles calling ice_put_rx_buf() for each buffer in the current frame. This function was introduced as part of handling multi-buffer XDP support in the ice driver. It works by iterating over the buffers from first_desc up to 1 plus the total number of fragments in the frame, cached from before the XDP program was executed. If the hardware posts a descriptor with a size of 0, the logic used in ice_put_rx_mbuf() breaks. Such descriptors get skipped and don't get added as fragments in ice_add_xdp_frag. Since the buffer isn't counted as a fragment, we do not iterate over it in ice_put_rx_mbuf(), and thus we don't call ice_put_rx_buf(). Because we don't call ice_put_rx_buf(), we don't attempt to re-use the page or free it. This leaves a stale page in the ring, as we don't increment next_to_alloc. The ice_reuse_rx_page() assumes that the next_to_alloc has been incremented properly, and that it always points to a buffer with a NULL page. Since this function doesn't check, it will happily recycle a page over the top of the next_to_alloc buffer, losing track of the old page. Note that this leak only occurs for multi-buffer frames. The ice_put_rx_mbuf() function always handles at least one buffer, so a single-buffer frame will always get handled correctly. It is not clear precisely why the hardware hands us descriptors with a size of 0 sometimes, but it happens somewhat regularly with "jumbo frames" used by 9K MTU. To fix ice_put_rx_mbuf(), we need to make sure to call ice_put_rx_buf() on all buffers between first_desc and next_to_clean. Borrow the logic of a similar function in i40e used for this same purpose. Use the same logic also in ice_get_pgcnts(). Instead of iterating over just the number of fragments, use a loop which iterates until the current index reaches to the next_to_clean element just past the current frame. Unlike i40e, the ice_put_rx_mbuf() function does call ice_put_rx_buf() on the last buffer of the frame indicating the end of packet. For non-linear (multi-buffer) frames, we need to take care when adjusting the pagecnt_bias. An XDP program might release fragments from the tail of the frame, in which case that fragment page is already released. Only update the pagecnt_bias for the first descriptor and fragments still remaining post-XDP program. Take care to only access the shared info for fragmented buffers, as this avoids a significant cache miss. The xdp_xmit value only needs to be updated if an XDP program is run, and only once per packet. Drop the xdp_xmit pointer argument from ice_put_rx_mbuf(). Instead, set xdp_xmit in the ice_clean_rx_irq() function directly. This avoids needing to pass the argument and avoids an extra bit-wise OR for each buffer in the frame. Move the increment of the ntc local variable to ensure its updated *before* all calls to ice_get_pgcnts() or ice_put_rx_mbuf(), as the loop logic requires the index of the element just after the current frame. Now that we use an index pointer in the ring to identify the packet, we no longer need to track or cache the number of fragments in the rx_ring.

It is possible to read the advisory at git.kernel.org. This vulnerability is uniquely identified as CVE-2025-39948 since 04/16/2025. The exploitability is told to be easy. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 01/27/2026).

The vulnerability scanner Nessus provides a plugin with the ID 269454 (Linux Distros Unpatched Vulnerability : CVE-2025-39948), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.12.49 or 6.16.9 eliminates this vulnerability. Applying the patch 80555adb5c892f0e21d243ae96ed997ee520aea9/fcb5718ebfe7fd64144e3399280440cce361a3ae/84bf1ac85af84d354c7a2fdbdc0d4efc8aaec34b 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 databases at Tenable (269454) and CERT Bund (WID-SEC-2025-2194). Be aware that VulDB is the high quality source for vulnerability data.

Affected

• Google Container-Optimized OS
• Debian Linux
• Google Cloud Platform
• Amazon Linux 2
• Red Hat Enterprise Linux
• Ubuntu Linux
• SUSE Linux
• Oracle Linux
• SUSE openSUSE
• Open Source Linux Kernel
• RESF Rocky Linux
• IBM QRadar SIEM

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.12.0
• 6.12.1
• 6.12.2
• 6.12.3
• 6.12.4
• 6.12.5
• 6.12.6
• 6.12.7
• 6.12.8
• 6.12.9
• 6.12.10
• 6.12.11
• 6.12.12
• 6.12.13
• 6.12.14
• 6.12.15
• 6.12.16
• 6.12.17
• 6.12.18
• 6.12.19
• 6.12.20
• 6.12.21
• 6.12.22
• 6.12.23
• 6.12.24
• 6.12.25
• 6.12.26
• 6.12.27
• 6.12.28
• 6.12.29
• 6.12.30
• 6.12.31
• 6.12.32
• 6.12.33
• 6.12.34
• 6.12.35
• 6.12.36
• 6.12.37
• 6.12.38
• 6.12.39
• 6.12.40
• 6.12.41
• 6.12.42
• 6.12.43
• 6.12.44
• 6.12.45
• 6.12.46
• 6.12.47
• 6.12.48
• 6.16.0
• 6.16.1
• 6.16.2
• 6.16.3
• 6.16.4
• 6.16.5
• 6.16.6
• 6.16.7
• 6.16.8

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

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Entryinfo

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