CyberSecBulletin
CVE-2025-68785NVD status: Deferred

Linux: Out-of-bounds Read

Published Updated By the CyberSecBulletin desk

CVE-2025-68785 is a high-severity out-of-bounds read vulnerability in Linux, with a CVSS 3.1 base score of 7.1 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions d0c135b8bbbcf92836068fd395bebeb7ae6c7bef, 3bc2efff20a38b2c7ca18317649715df0dd62ced, 1b569db9c2f28b599e40050524aae5f7332bc294 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.16% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to d0c135b8bbbcf92836068fd395bebeb7ae6c7bef or 3bc2efff20a38b2c7ca18317649715df0dd62ced or 1b569db9c2f28b599e40050524aae5f7332bc294 or 10ffc558246f2c75619aedda0921906095e46702, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinuxb2d0f5d5dc53532e6f07bc546a476a55ebdfe0f3 up to, but not including, d0c135b8bbbcf92836068fd395bebeb7ae6c7bef; b2d0f5d5dc53532e6f07bc546a476a55ebdfe0f3 up to, but not including, 3bc2efff20a38b2c7ca18317649715df0dd62ced; b2d0f5d5dc53532e6f07bc546a476a55ebdfe0f3 up to, but not including, 1b569db9c2f28b599e40050524aae5f7332bc294; b2d0f5d5dc53532e6f07bc546a476a55ebdfe0f3 up to, but not including, 10ffc558246f2c75619aedda0921906095e46702; b2d0f5d5dc53532e6f07bc546a476a55ebdfe0f3 up to, but not including, 2ecfc4433acdb149eafd7fb22d7fd4adf90b25e9; b2d0f5d5dc53532e6f07bc546a476a55ebdfe0f3 up to, but not including, c999153bfb2d1d9b295b7010d920f2a7c6d7595f; b2d0f5d5dc53532e6f07bc546a476a55ebdfe0f3 up to, but not including, 5ace7ef87f059d68b5f50837ef3e8a1a4870c36e; 4.15d0c135b8bbbcf92836068fd395bebeb7ae6c7bef, 3bc2efff20a38b2c7ca18317649715df0dd62ced, 1b569db9c2f28b599e40050524aae5f7332bc294, 10ffc558246f2c75619aedda0921906095e46702, 2ecfc4433acdb149eafd7fb22d7fd4adf90b25e9, c999153bfb2d1d9b295b7010d920f2a7c6d7595f

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
LocalThe attacker needs local access or must trick a user into running something.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
NoneNothing can be modified.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H. Scored by CNA.

Official description

In the Linux kernel, the following vulnerability has been resolved: net: openvswitch: fix middle attribute validation in push_nsh() action The push_nsh() action structure looks like this: OVS_ACTION_ATTR_PUSH_NSH(OVS_KEY_ATTR_NSH(OVS_NSH_KEY_ATTR_BASE,...)) The outermost OVS_ACTION_ATTR_PUSH_NSH attribute is OK'ed by the nla_for_each_nested() inside __ovs_nla_copy_actions(). The innermost OVS_NSH_KEY_ATTR_BASE/MD1/MD2 are OK'ed by the nla_for_each_nested() inside nsh_key_put_from_nlattr(). But nothing checks if the attribute in the middle is OK. We don't even check that this attribute is the OVS_KEY_ATTR_NSH. We just do a double unwrap with a pair of nla_data() calls - first time directly while calling validate_push_nsh() and the second time as part of the nla_for_each_nested() macro, which isn't safe, potentially causing invalid memory access if the size of this attribute is incorrect. The failure may not be noticed during validation due to larger netlink buffer, but cause trouble later during action execution where the buffer is allocated exactly to the size: BUG: KASAN: slab-out-of-bounds in nsh_hdr_from_nlattr+0x1dd/0x6a0 [openvswitch] Read of size 184 at addr ffff88816459a634 by task a.out/22624 CPU: 8 UID: 0 PID: 22624 6.18.0-rc7+ #115 PREEMPT(voluntary) Call Trace: <TASK> dump_stack_lvl+0x51/0x70 print_address_description.constprop.0+0x2c/0x390 kasan_report+0xdd/0x110 kasan_check_range+0x35/0x1b0 __asan_memcpy+0x20/0x60 nsh_hdr_from_nlattr+0x1dd/0x6a0 [openvswitch] push_nsh+0x82/0x120 [openvswitch] do_execute_actions+0x1405/0x2840 [openvswitch] ovs_execute_actions+0xd5/0x3b0 [openvswitch] ovs_packet_cmd_execute+0x949/0xdb0 [openvswitch] genl_family_rcv_msg_doit+0x1d6/0x2b0 genl_family_rcv_msg+0x336/0x580 genl_rcv_msg+0x9f/0x130 netlink_rcv_skb+0x11f/0x370 genl_rcv+0x24/0x40 netlink_unicast+0x73e/0xaa0 netlink_sendmsg+0x744/0xbf0 __sys_sendto+0x3d6/0x450 do_syscall_64+0x79/0x2c0 entry_SYSCALL_64_after_hwframe+0x76/0x7e </TASK> Let's add some checks that the attribute is properly sized and it's the only one attribute inside the action. Technically, there is no real reason for OVS_KEY_ATTR_NSH to be there, as we know that we're pushing an NSH header already, it just creates extra nesting, but that's how uAPI works today. So, keeping as it is.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Out-of-bounds Read

The product reads data past the end, or before the beginning, of the intended buffer.

How developers prevent this class of flaw

  • Use a language that provides appropriate memory abstractions.

More Out-of-bounds Read vulnerabilities (CWE-125)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Out-of-bounds Read vulnerabilities

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