high CVSS 7.1

CVE-2024-26665·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: tunnels: fix out of bounds access when building IPv6 PMTU error If the ICMPv6 error is built from a non-linear skb we get the following splat, BUG: KASAN: slab-out-of-bounds in do_csum+0x220/0x240 Read of size 4 at addr ffff88811d402c80 by task netperf/820 CPU: 0 PID: 820 Comm: netperf Not tainted 6.8.0-rc1+ #543 ... kasan_report+0xd8/0x110 do_csum+0x220/0x240 csum_partial+0xc/0x20 skb_tunnel_check_pmtu+0xeb9/0x3280 vxlan_xmit_one+0x14c2/0x4080 vxlan_xmit+0xf61/0x5c00 dev_hard_start_xmit+0xfb/0x510 __dev_queue_xmit+0x7cd/0x32a0 br_dev_queue_push_xmit+0x39d/0x6a0 Use skb_checksum instead of csum_partial who cannot deal with non-linear SKBs.

Severity
high
Software
Kernel
Fixed in
6.7.5
Published
2024-04-02

Affected versions

From: 6.7

Until: 6.7.5

Fixed in: 6.7.5

How to fix this CVE

Update your Linux kernel to version 6.7.5 or later to resolve a memory safety issue in IPv6 PMTU error handling. This vulnerability affects tunnel implementations (such as VXLAN) when processing non-linear network packets. Ensure your system is running the patched kernel version and reboot if necessary to apply the fix.

sudo dnf update kernel kernel-devel

Defensia detects this vulnerability

How to check if you are affected

  1. Step 1: Check installed kernel version with `uname -r` and compare against 6.7.5 or later
  2. Step 2: Verify if tunnel modules (vxlan, geneve, etc.) are loaded with `lsmod | grep -E '(vxlan|geneve|tunnel)'`
  3. Step 3: Search kernel logs for KASAN slab-out-of-bounds errors with `dmesg | grep -i 'kasan.*slab-out-of-bounds'` or `journalctl -k | grep -i 'slab-out-of-bounds'`
  4. Step 4: After patching, confirm the new kernel version is active with `uname -r` and verify no KASAN errors in recent logs

FAQ

What is CVE-2024-26665?

This vulnerability is a memory access violation in the Linux kernel's tunnel PMTU error handling path. When processing IPv6 Path MTU Discovery errors on non-linear socket buffers (skbs), the kernel incorrectly uses a function that cannot handle fragmented packets, causing out-of-bounds memory reads and potential system crashes.

Is CVE-2024-26665 being actively exploited?

No, this vulnerability is not listed as actively exploited by CISA and has no public exploits available. However, it can be triggered locally by unprivileged users on systems with tunnel configurations.

What versions of Kernel are affected by CVE-2024-26665?

Linux kernel versions 6.7 through 6.7.4 are vulnerable. The fix is included in version 6.7.5 and later.

How do I check if my server is vulnerable to CVE-2024-26665?

Run `uname -r` and check if your kernel version is between 6.7 and 6.7.4. Additionally, run `lsmod | grep -E '(vxlan|geneve|tunnel)'` to confirm if tunnel modules are active on your system.

Does Defensia detect CVE-2024-26665?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If the Linux kernel is installed on a monitored server, CVE-2024-26665 will appear in your dashboard with remediation steps.

Related Kernel CVEs

CVE-2026-100075CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: RDMA/srpt: Fix srpt_alloc_rw_ctxs() unwind counters When srpt_alloc_rw_ctxs() fails partway through a multi-buffer indirect descriptor, the unwind path destroys RDMA contexts but leaves stale n_rw_ctx and n_rdma values (and a dangling rw_ctxs pointer). Later sq_wr_avail accounting in srpt_queue_response() or srpt_write_pending() can then subtract the wrong number of send queue credits. Reset the counters and clear rw_ctxs after freeing the heap allocation before returning an error.
CVE-2026-64035CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: igc: set tx buffer type for SMD frames Sashiko pointed out that igc_fpe_init_smd_frame() initializes igc_tx_buffer fields for an SMD skb, but does not set the buffer type: https://sashiko.dev/#/patchset/20260415025226.114115-1-kohei%40enjuk.jp Since igc_tx_buffer entries are reused, a stale XDP or XSK type can remain and make TX completion use the wrong cleanup path. Set the buffer type to IGC_TX_BUFFER_TYPE_SKB.
CVE-2026-64033CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: RDMA/rtrs: Fix use-after-free in path file creation cleanup In the error path of rtrs_srv_create_path_files(), the sysfs root folders may already have been created and srv_path->kobj may already have been initialized. If a later step fails, the cleanup currently calls kobject_put(&srv_path->kobj) before rtrs_srv_destroy_once_sysfs_root_folders(srv_path). kobject_put() may drop the last reference to srv_path->kobj and invoke the release callback, rtrs_srv_release(), which frees srv_path. The following call to rtrs_srv_destroy_once_sysfs_root_folders(srv_path) then dereferences srv_path internally to access srv_path->srv, resulting in a use-after-free. This failure path is reached before rtrs_srv_create_path_files() returns success, so the successful-path lifetime handling is not involved. Fix this by destroying the sysfs root folders before calling kobject_put(&srv_path->kobj), so srv_path is still valid while the helper accesses it. This issue was found by a static analysis tool I am developing.
CVE-2026-64037CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: wifi: iwlwifi: mld: fix TSO segmentation explosion when AMSDU is disabled When the TLC notification disables AMSDU for a TID, the MLD driver sets max_tid_amsdu_len to the sentinel value 1. The TSO segmentation path in iwl_mld_tx_tso_segment() checks for zero but not for this sentinel, allowing it to reach the num_subframes calculation: num_subframes = (max_tid_amsdu_len + pad) / (subf_len + pad) = (1 + 2) / (1534 + 2) = 0 This zero propagates to iwl_tx_tso_segment() which sets: gso_size = num_subframes * mss = 0 Calling skb_gso_segment() with gso_size=0 creates over 32000 tiny segments from a single GSO skb. This floods the TX ring with ~1024 micro-frames (the rest are purged), creating a massive burst of TX completion events that can lead to memory corruption and a subsequent use-after-free in TCP's retransmit queue (refcount underflow in tcp_shifted_skb, NULL deref in tcp_rack_detect_loss). The MVM driver is immune because it checks mvmsta->amsdu_enabled before reaching the num_subframes calculation. The MLD driver has no equivalent bitmap check and relies solely on max_tid_amsdu_len, which does not catch the sentinel value. Fix this by detecting the sentinel value (max_tid_amsdu_len == 1) at the existing check and falling back to non-AMSDU TSO segmentation. Also add a WARN_ON_ONCE guard after the num_subframes division as defense-in-depth to catch any future code paths that produce zero through a different mechanism.
CVE-2026-64000CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: net: hsr: fix potential OOB access in supervision frame handling Ensure the entire TLV header is linearized before access by adding sizeof(struct hsr_sup_tlv) to the pskb_may_pull() calls. Without this, a truncated frame could cause an out-of-bounds access.

References

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