CVE-2026-64089
Linux Kernel vulnerability
- Published19 Jul 2026
Description
In the Linux kernel, the following vulnerability has been resolved: batman-adv: tt: fix negative last_changeset_len batadv_piv_tt::last_changeset_len len was declared as s16, but the field is never intended to hold a negative value. When a value greater than 32767 is assigned, it wraps to a negative signed integer. In batadv_send_my_tt_response(), last_changeset_len is temporarily widened to s32. The incorrectly negative s16 value propagates into the s32, causing batadv_tt_prepare_tvlv_local_data() to allocate a full sized buffer but populates only a small portion of it with the collected changeset. All remaining bits are kept uninitialized. Using an u16 avoids this type confusion and ensures that no (negative) sign extension is performed in batadv_send_my_tt_response().
CVSS 3.1 breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HAffected products
Remediation
- https://git.kernel.org/stable/c/179eb62506a02d00370bd6478898cb632e10986c
- https://git.kernel.org/stable/c/22d59c72f4a47ffec121d0610f70d0d70c3c11c8
- https://git.kernel.org/stable/c/55dc41fe8821e9a849e147255ad572bc933a9d15
- https://git.kernel.org/stable/c/6314089acf0ddf64376fdc0b1420695504c73f52
- https://git.kernel.org/stable/c/c424e8519ac78eac5d9f4eecf06208a0d619ec14
- https://git.kernel.org/stable/c/d29abf70c665730e249d2ec8e1402095ae26bcee
References
- https://git.kernel.org/stable/c/179eb62506a02d00370bd6478898cb632e10986c
- https://git.kernel.org/stable/c/22d59c72f4a47ffec121d0610f70d0d70c3c11c8
- https://git.kernel.org/stable/c/55dc41fe8821e9a849e147255ad572bc933a9d15
- https://git.kernel.org/stable/c/6314089acf0ddf64376fdc0b1420695504c73f52
- https://git.kernel.org/stable/c/c424e8519ac78eac5d9f4eecf06208a0d619ec14
- https://git.kernel.org/stable/c/d29abf70c665730e249d2ec8e1402095ae26bcee
- https://git.kernel.org/stable/c/eb235472b52ef36981c5aad330485eaf2382c53b
- https://git.kernel.org/stable/c/fc92cdfcb295cefa4344d71a527d61b638b7bfc4
Frequently asked
Is CVE-2026-64089 being actively exploited?
CVE-2026-64089 is not in the CISA KEV catalog. Its EPSS exploit probability is 0.55%.
How severe is CVE-2026-64089?
CVE-2026-64089 has a CVSS 3.1 base score of 9.8, rated critical. EPSS estimates a 0.55% probability of exploitation.
Which products are affected by CVE-2026-64089?
Affected products include Linux Kernel.
How do I fix CVE-2026-64089?
Upgrade affected software to a fixed version, for example Linux Kernel 5.10.258 or later, then confirm no affected versions remain in your inventory.
How Secuno handles this
Secuno correlates vulnerabilities like CVE-2026-64089 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.
Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.