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CVE-2026-64089· NVD / CVE Program· CNA Linux

batman-adv: tt: fix negative last_changeset_len

Noroxi assessment

Priority: Monitor (action score 39/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.55% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 179eb62506a02d00370bd6478898cb632e10986c, 22d59c72f4a47ffec121d0610f70d0d70c3c11c8, 55dc41fe8821e9a849e147255ad572bc933a9d15.

Low priority for now. Upgrade to Linux Linux 179eb62506a02d00370bd6478898cb632e10986c, 22d59c72f4a47ffec121d0610f70d0d70c3c11c8, 55dc41fe8821e9a849e147255ad572bc933a9d15 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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().

CriticalCVSS 9.8 · v3.1—No exploit Fix available
Published
Jul 19, 2026
Updated
Aug 11, 2026
EPSS
0.5% · 45th percentile
CWE
—

Report tools

JSON

Action score

39

Monitor

Low priority for now.

CVSS
39 / 40 · 9.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.5%

CNA vs NVD score

NVD
—
CNA · Linux
9.8
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel3.1 and later · before 5.10.258
  • linux linux kernel5.11 and later · before 5.15.209
  • linux linux kernel5.16 and later · before 6.1.175
  • linux linux kernel6.2 and later · before 6.6.142
  • linux linux kernel6.7 and later · before 6.12.92
  • linux linux kernel6.13 and later · before 6.18.34
  • linux linux kernel6.19 and later · before 7.0.11
  • linux linux kernel7.1

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 3.1affected
    • a73105b8d4c765d9ebfb664d0a66802127d8e4c7 and later · before 6314089acf0ddf64376fdc0b1420695504c73f52affected · git
    • a73105b8d4c765d9ebfb664d0a66802127d8e4c7 and later · before 55dc41fe8821e9a849e147255ad572bc933a9d15affected · git
    • a73105b8d4c765d9ebfb664d0a66802127d8e4c7 and later · before c424e8519ac78eac5d9f4eecf06208a0d619ec14affected · git
    • a73105b8d4c765d9ebfb664d0a66802127d8e4c7 and later · before 22d59c72f4a47ffec121d0610f70d0d70c3c11c8affected · git
    • a73105b8d4c765d9ebfb664d0a66802127d8e4c7 and later · before eb235472b52ef36981c5aad330485eaf2382c53baffected · git
    • a73105b8d4c765d9ebfb664d0a66802127d8e4c7 and later · before 179eb62506a02d00370bd6478898cb632e10986caffected · git
    • a73105b8d4c765d9ebfb664d0a66802127d8e4c7 and later · before d29abf70c665730e249d2ec8e1402095ae26bceeaffected · git
    • a73105b8d4c765d9ebfb664d0a66802127d8e4c7 and later · before fc92cdfcb295cefa4344d71a527d61b638b7bfc4affected · git
    • before 3.1not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.176-16.1.176-1
Debian:13linuxbefore 6.12.94-16.12.94-1
Debian:14linuxbefore 7.0.12-17.0.12-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now
  • CVE-2016-5195Race condition in mm/gup.c in the Linux kernel 2.x through 4.x before 4.8.3 allows local users to gain privileges by leveraging incorrect haKEV
    83Now

Published before and after this one in the same product

  • ← EarlierCVE-2026-64087Jul 19, 2026 · hwmon: (pmbus/adm1266) reject implausible blackbox record_count
    22Monitor
  • ← EarlierCVE-2026-64088Jul 19, 2026 · batman-adv: tt: fix negative tt_buff_len
    35Monitor
  • Later →CVE-2026-64090Jul 19, 2026 · batman-adv: tt: avoid empty VLAN responses
    22Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux179eb62506a02d00370bd6478898cb632e10986cVendor (CNA)
Linux Linux22d59c72f4a47ffec121d0610f70d0d70c3c11c8Vendor (CNA)
Linux Linux55dc41fe8821e9a849e147255ad572bc933a9d15Vendor (CNA)
Linux Linux6314089acf0ddf64376fdc0b1420695504c73f52Vendor (CNA)
Linux Linuxc424e8519ac78eac5d9f4eecf06208a0d619ec14Vendor (CNA)
Linux Linuxd29abf70c665730e249d2ec8e1402095ae26bceeVendor (CNA)
Linux Linuxeb235472b52ef36981c5aad330485eaf2382c53bVendor (CNA)
Linux Linuxfc92cdfcb295cefa4344d71a527d61b638b7bfc4Vendor (CNA)
debian:linux6.1.176-1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

—

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (7 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records