Linux: Use of Uninitialized Resource
CVE-2026-63870 is a high-severity use of uninitialized resource vulnerability in Linux, with a CVSS 3.1 base score of 7.8 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 af07fffbd53ddc3ec3c2a4ca914f27899fa89bca, 3150e6d3223dfc356308125cabf9c34169842d2a, 8da95cb6ad7d656c871e776a9c7b77e894d6d89c 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 0.17% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to af07fffbd53ddc3ec3c2a4ca914f27899fa89bca or 3150e6d3223dfc356308125cabf9c34169842d2a or 8da95cb6ad7d656c871e776a9c7b77e894d6d89c or 1a827b95e62b4cbe851ae7cc9c961cdfa769cca4, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.10.259 or 5.15.210 or 6.1.176 or 6.6.143, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 4dc315e267fe4a3c863fec21f26aa0a418c3f07a up to, but not including, af07fffbd53ddc3ec3c2a4ca914f27899fa89bca; 4dc315e267fe4a3c863fec21f26aa0a418c3f07a up to, but not including, 3150e6d3223dfc356308125cabf9c34169842d2a; 4dc315e267fe4a3c863fec21f26aa0a418c3f07a up to, but not including, 8da95cb6ad7d656c871e776a9c7b77e894d6d89c; 4dc315e267fe4a3c863fec21f26aa0a418c3f07a up to, but not including, 1a827b95e62b4cbe851ae7cc9c961cdfa769cca4; 4dc315e267fe4a3c863fec21f26aa0a418c3f07a up to, but not including, c1819c8defa235c7beda859bc185b1c429a55ecd; 4dc315e267fe4a3c863fec21f26aa0a418c3f07a up to, but not including, 285b0842f2e01c3edf805f1fd64da11d9b7f6b4c; 4dc315e267fe4a3c863fec21f26aa0a418c3f07a up to, but not including, 87172cc8dc49aaf54407a31edffb0232f8cb93ab; 4dc315e267fe4a3c863fec21f26aa0a418c3f07a up to, but not including, 3a5f3f7aff18bcc36a57839cf50cf0cc8de707f3; and 1 more ranges | af07fffbd53ddc3ec3c2a4ca914f27899fa89bca, 3150e6d3223dfc356308125cabf9c34169842d2a, 8da95cb6ad7d656c871e776a9c7b77e894d6d89c, 1a827b95e62b4cbe851ae7cc9c961cdfa769cca4, c1819c8defa235c7beda859bc185b1c429a55ecd, 285b0842f2e01c3edf805f1fd64da11d9b7f6b4c |
| Linux | Linux Kernel | 4.0 up to, but not including, 5.10.259; 5.11 up to, but not including, 5.15.210; 5.16 up to, but not including, 6.1.176; 6.2 up to, but not including, 6.6.143; 6.7 up to, but not including, 6.12.94; 6.13 up to, but not including, 6.18.36; 6.19 up to, but not including, 7.0.13; 7.1 | 5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.94, 6.18.36 |
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
- HighData or code can be modified at will.
- 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:H/A:H. Scored by CNA.
Official description
In the Linux kernel, the following vulnerability has been resolved: ieee802154: 6lowpan: only accept IPv6 packets in lowpan_xmit() The aoe driver (or similar) generates a non-IPv6 packet (e.g., ETH_P_AOE) and queues it for transmission via dev_queue_xmit() on a 6LoWPAN interface (configured by the user or test case). Since the packet is not IPv6, the 6LoWPAN header_ops->create function (lowpan_header_create or header_create) returns early without initializing the lowpan_addr_info structure in the skb headroom. In the transmit function (lowpan_xmit), the driver calls lowpan_header (or setup_header) which unconditionally copies and uses the lowpan_addr_info from the headroom, which contains uninitialized data. Fix this by dropping non IPv6 packets. A similar fix is needed in net/bluetooth/6lowpan.c bt_xmit().
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use of Uninitialized Resource
The product uses or accesses a resource that has not been initialized.
How developers prevent this class of flaw
- Explicitly initialize the resource before use. If this is performed through an API function or standard procedure, follow all required steps.
- Pay close attention to complex conditionals that affect initialization, since some branches might not perform the initialization.
- Avoid race conditions (CWE-362) during initialization routines.
More Use of Uninitialized Resource vulnerabilities (CWE-908)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/1a827b95e62b4cbe851ae7cc9c961cdfa769cca4
- git.kernel.org/stable/c/285b0842f2e01c3edf805f1fd64da11d9b7f6b4c
- git.kernel.org/stable/c/3150e6d3223dfc356308125cabf9c34169842d2a
- git.kernel.org/stable/c/3a5f3f7aff18bcc36a57839cf50cf0cc8de707f3
- git.kernel.org/stable/c/87172cc8dc49aaf54407a31edffb0232f8cb93ab
- git.kernel.org/stable/c/8da95cb6ad7d656c871e776a9c7b77e894d6d89c
- git.kernel.org/stable/c/af07fffbd53ddc3ec3c2a4ca914f27899fa89bca
- git.kernel.org/stable/c/c1819c8defa235c7beda859bc185b1c429a55ecd
Recent Use of Uninitialized Resource vulnerabilities
- 7.8 High severity
- 9.8 Critical severity
- 8.2 High severity
- 9.1 Critical severity
- 8.8 High severity
- 9.8 Critical severity
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