# CVE-2025-39948: ice: fix Rx page leak on multi-buffer frames > A memory leak in the Intel ice network driver can cause resource exhaustion and denial of service when processing multi-buffer frames with zero-size descriptors. - **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 4 Oct 2025 - **Updated:** 21 Oct 2026 - **Also known as:** AZL-75296, BELL-CVE-2025-39948, DEBIAN-CVE-2025-39948, GHSA-7v58-mp27-j7rx, ROOT-OS-DEBIAN-13-CVE-2025-39948, ROOT-OS-UBUNTU-2404-CVE-2025-39948, UBUNTU-CVE-2025-39948 ## What is CVE-2025-39948? CVE-2025-39948 is a critical denial of service vulnerability in Linux kernel, published on 4 Oct 2025. 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: 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. Weakness: CWE-401 (Missing Release of Memory after Effective Lifetime) ## Which versions are affected by CVE-2025-39948? It affects 1 product. Products: Linux kernel. ## How do I fix CVE-2025-39948? Apply the vendor's patch. ## Is CVE-2025-39948 being exploited? There is no known exploitation of CVE-2025-39948 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-2025-39948 and fix it if it is affected. What it is: CVE-2025-39948 is a critical denial of service vulnerability in Linux kernel, published on 4 Oct 2025. 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-2025-39948 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-2025-39948/ (Markdown: https://insights.sbomify.com/CVE-2025-39948/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2025-39948 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-39948 - OSV: https://osv.dev/vulnerability/CVE-2025-39948 --- From sbomify Insights: https://insights.sbomify.com/CVE-2025-39948/ Summaries are generated and may contain mistakes; the official description above is the record.