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Review reviewCritical

CVE-2026-64089

Linux

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 c...

CVSS
9.8
EPSS
-
- percentile
CISA KEV
Not listed
Published
2026.07.20
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability-
Technical severityCVSS 9.8

Vulnerability overview

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 c...

Affected product and versions

Product
Linux
Affected versions
>= a73105b8d4c765d9ebfb664d0a66802127d8e4c7 < 6314089acf0ddf64376fdc0b1420695504c73f52, >= a73105b8d4c765d9ebfb664d0a66802127d8e4c7 < 55dc41fe8821e9a849e147255ad572bc933a9d15, >= a73105b8d4c765d9ebfb664d0a66802127d8e4c7 < c424e8519ac78eac5d9f4eecf06208a0d619ec14, >= a73105b8d4c765d9ebfb664d0a66802127d8e4c7 < 22d59c72f4a47ffec121d0610f70d0d70c3c11c8, >= a73105b8d4c765d9ebfb664d0a66802127d8e4c7 < eb235472b52ef36981c5aad330485eaf2382c53b, >= a73105b8d4c765d9ebfb664d0a66802127d8e4c7 < 179eb62506a02d00370bd6478898cb632e10986c, >= a73105b8d4c765d9ebfb664d0a66802127d8e4c7 < d29abf70c665730e249d2ec8e1402095ae26bcee, >= a73105b8d4c765d9ebfb664d0a66802127d8e4c7 < fc92cdfcb295cefa4344d71a527d61b638b7bfc4, >= 3.1
Fixed versions
No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that Linux and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE
Not available
CVE-2026-64089 — Linux | SECUFOCUS NOW