CVE-2026-64088: batman-adv: tt: fix negative tt_buff_len
In the Linux kernel, the following vulnerability has been resolved:
batman-adv: tt: fix negative ttbufflen
batadvorignode::ttbufflen 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 batadvsendotherttresponse(), ttbufflen is temporarily widened to s32. The incorrectly negative s16 value propagates into the s32, causing batadvttpreparetvlvglobaldata() 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 batadvsendotherttresponse().
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Linux kernelto a version that resolves this vulnerability.Patch batman-adv: tt: fix negative tt_buff_len
Event History
Frequently Asked Questions
What is the severity of CVE-2026-64088?
CVE-2026-64088 is rated with a risk score of 37.
How do I fix CVE-2026-64088?
To fix CVE-2026-64088, update your Linux kernel to the latest version that includes the patch.
What components are affected by CVE-2026-64088?
CVE-2026-64088 affects the batman-adv module in the Linux kernel.
What is the nature of the vulnerability in CVE-2026-64088?
CVE-2026-64088 involves the improper handling of the tt_buff_len field, which can lead to negative values being incorrectly processed.
When was CVE-2026-64088 published?
CVE-2026-64088 was published on July 19, 2026.