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Fencer Vulns
critical 9.8

CVE-2025-39948 in the critical feed json

ice: fix Rx page leak on multi-buffer frames

published 2025-10-04 13 mo ago modified 2026-10-21 19 d ago also EUVD-2025-32395

cvss
9.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 34%
public exploits
0
none known

Summary

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.

Patch / fix

  • Linux Linux 6.6.160, 6.12.49, 6.14, 6.16.9, 6.17
  • linux Debian 13 6.12.57-1
  • linux Debian 14 6.16.9-1

debian advisories DEBIAN-CVE-2025-39948

  • linux Ubuntu 24.04 LTS 6.8.0-106.106
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1050.53
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1052.55
  • linux-gke Ubuntu 24.04 LTS 6.8.0-1048.53
  • linux-ibm Ubuntu 24.04 LTS 6.8.0-1049.49
  • linux-azure Ubuntu 24.04 LTS 6.8.0-1051.57
  • linux-gkeop Ubuntu 24.04 LTS 6.8.0-1035.38
  • linux-raspi Ubuntu 24.04 LTS 6.8.0-1050.54

ubuntu advisories UBUNTU-CVE-2025-39948

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel-rt Real Time Module 15 SP6, openSUSE Leap 15.6 6.4.0-150600.10.58.1
  • kernel-syms-rt Real Time Module 15 SP6, openSUSE Leap 15.6 6.4.0-150600.10.58.1
  • kernel-rt_debug Real Time Module 15 SP6, openSUSE Leap 15.6 6.4.0-150600.10.58.1
  • kernel-source-rt Real Time Module 15 SP6, openSUSE Leap 15.6 6.4.0-150600.10.58.1
  • kernel-rt Linux Micro 6.2 6.12.0-160000.7.1
  • kernel-64kb SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.7.1
  • kernel-source SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.7.1
  • kernel-default SLES 16.0, SLE High Availability Extension 16.0, Linux Micro 6.2 +1 more 6.12.0-160000.7.1

suse advisories SUSE-SU-2025:4301-1SUSE-SU-2025:21080-1SUSE-SU-2025:21147-1SUSE-SU-2025:21180-1SUSE-SU-2026:20561-1SUSE-SU-2025:21052-1

  • kernel-rt openSUSE Leap 16.0 6.12.0-160000.7.1
  • dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.7.1
  • kernel-64kb openSUSE Leap 16.0 6.12.0-160000.7.1
  • kernel-syms openSUSE Leap 16.0 6.12.0-160000.7.1
  • kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.7.1
  • kernel-source openSUSE Leap 16.0 6.12.0-160000.7.1
  • kernel-default openSUSE Leap 16.0 6.12.0-160000.7.1
  • kernel-kvmsmall openSUSE Leap 16.0 6.12.0-160000.7.1

opensuse advisories openSUSE-SU-2025:20091-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-39948 updated cvss 6.4

kernel: ice: fix Rx page leak on multi-buffer frames

  • Red Hat Enterprise Linux 9 kernel-rt, kernel-rt-selftests-internal Red Hat Enterprise Linux 10 kernel
    affected: workaround, no fix available
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +82 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.40% chance of exploitation in the next 30 days, higher than 34% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Linux Linux

Classification

Weakness
  • CWE-401 Missing Release of Memory after Effective Lifetime
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.