CVE-2026-80839
UnknownSummary
In the Linux kernel's batman-adv module, there is an out-of-bounds read vulnerability. The batadv_tvlv_call_handler() function sets the network_header and transport_header fields in the sk_buff structure based on a received multicast TVLV, without checking whether the end offset is representable in a 16-bit field. If the offset exceeds the range, skb_set_transport_header() truncates it, causing the transport header to precede the network header, and skb_network_header_len() returns a large u32 value. The batadv_mcast_forw_packet() function then accepts an oversized multicast tracker and accesses memory beyond the skb data. The fix adds the skb_set_transport_header_careful() function and rejects unrepresentable TVLVs.
Risk Assessment
An attacker in a mesh network (batman-adv) can send a specially crafted multicast packet, potentially leading to kernel memory disclosure or system crash.
Recommendation
Install the Linux kernel update containing the fix for batman-adv. Limit trust in mesh network nodes.
Other vulnerabilities in Linux kernel
See all- CVE-2026-98163Unknown
A vulnerability was found in the Linux kernel's cgroup subsystem, involving iteration over dying tasks with a zero reference count. This leads to a race condition where the iterator may access a task after it has been freed, resulting in a use-after-free.
- CVE-2026-98162Unknown
In the Linux kernel, the smb2_tree_connect() function of the SMB server (ksmbd) leaks a tree connection. When ksmbd_iov_pin_rsp() fails, the newly created tree connection is not disconnected, leading to a resource leak.
- CVE-2026-98161Unknown
In the Linux kernel, the nvdimm (pmem) pmem_submit_bio() function records a REQ_PREFLUSH error but continues to copy bio data and can later overwrite the error with a successful REQ_FUA flush. This allows data writes to run after a failed preflush and can complete the bio successfully despite the failed ordering barrier.
- CVE-2026-98160Unknown
In the Linux kernel, the staging rtl8723bs driver's rtw_sdio_if1_init() function frees padapter->HalData with kfree(), even though it was allocated via vzalloc(). Using kfree() to release a vmalloc-backed buffer can lead to memory corruption.
- CVE-2026-100079Unknown
In the Linux kernel, the USB Type-C (ucsi) subsystem's ucsi_register() creates per-instance debugfs entries, but ucsi_unregister() keeps them until ucsi_destroy(). Drivers like ucsi_glink that unregister/register the same UCSI instance across remoteproc restart then try to create an already existing debugfs directory.
- CVE-2026-100078Unknown
In the Linux kernel, the iwlwifi (mei) driver's iwl_mei_write_cyclic_buf() function receives an incorrect first argument — the q_head pointer is passed instead of cldev. The bug has been fixed.
- CVE-2026-100077Unknown
In the Linux kernel, the drm/msm driver does not safely retire a hung submit before GPU recovery completes. Retiring the submit triggers BO free, which can result in GPU pagefaults since the GPU may be actively accessing those BOs.
- CVE-2026-100074Unknown
In the Linux kernel, a bug was fixed where the BPF_REFCOUNT field was not marked as unique, although it should be. The fix addresses this oversight.
- CVE-2026-100073Unknown
In the Linux kernel, a bug in the ext4 filesystem related to transaction overflow during writeback was fixed. A previous fix was too eager in reducing reserved transaction credits, leading to insufficient reservation in some corner cases. The fix uses ext4_meta_trans_blocks() for a correct upper bound estimate.
- CVE-2026-100072Unknown
In the Linux kernel, a problem in the ACPI subsystem was fixed where the use of acpi_get_first_physical_node() in acpi_platform_fill_resource() and acpi_create_platform_device() was unsafe because the returned device could be freed at any time. The fix replaces it with acpi_bus_get_primary_device() and adjusts the code to call it only once.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: batman-adv: reject unrepresentable multicast TVLV offsets The network and transport header fields in struct sk_buff are 16-bit offsets from skb->head, and U16_MAX is reserved as the unset transport header value. batadv_tvlv_call_handler() sets both fields from a received multicast TVLV without checking whether the TVLV end is representable. If the end offset exceeds the field's range, skb_set_transport_header() truncates it so that the transport header precedes the network header. The negative difference is then returned by skb_network_header_len() as a large u32. batadv_mcast_forw_packet() consequently accepts an oversized multicast tracker and accesses memory beyond the skb data. Add skb_set_transport_header_careful(), an offset-aware counterpart to skb_reset_transport_header_careful(), which validates the final head-relative offset before assigning it. Use the new helper in batadv_tvlv_call_handler() and reject unrepresentable TVLVs before setting the network header.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS