FKIE_CVE-2026-64089
Vulnerability from fkie_nvd - Published: 2026-07-19 16:17 - Updated: 2026-07-20 15:17
Severity
Summary
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().
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"net/batman-adv/types.h"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "6314089acf0ddf64376fdc0b1420695504c73f52",
"status": "affected",
"version": "a73105b8d4c765d9ebfb664d0a66802127d8e4c7",
"versionType": "git"
},
{
"lessThan": "55dc41fe8821e9a849e147255ad572bc933a9d15",
"status": "affected",
"version": "a73105b8d4c765d9ebfb664d0a66802127d8e4c7",
"versionType": "git"
},
{
"lessThan": "c424e8519ac78eac5d9f4eecf06208a0d619ec14",
"status": "affected",
"version": "a73105b8d4c765d9ebfb664d0a66802127d8e4c7",
"versionType": "git"
},
{
"lessThan": "22d59c72f4a47ffec121d0610f70d0d70c3c11c8",
"status": "affected",
"version": "a73105b8d4c765d9ebfb664d0a66802127d8e4c7",
"versionType": "git"
},
{
"lessThan": "eb235472b52ef36981c5aad330485eaf2382c53b",
"status": "affected",
"version": "a73105b8d4c765d9ebfb664d0a66802127d8e4c7",
"versionType": "git"
},
{
"lessThan": "179eb62506a02d00370bd6478898cb632e10986c",
"status": "affected",
"version": "a73105b8d4c765d9ebfb664d0a66802127d8e4c7",
"versionType": "git"
},
{
"lessThan": "d29abf70c665730e249d2ec8e1402095ae26bcee",
"status": "affected",
"version": "a73105b8d4c765d9ebfb664d0a66802127d8e4c7",
"versionType": "git"
},
{
"lessThan": "fc92cdfcb295cefa4344d71a527d61b638b7bfc4",
"status": "affected",
"version": "a73105b8d4c765d9ebfb664d0a66802127d8e4c7",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"net/batman-adv/types.h"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "3.1"
},
{
"lessThan": "3.1",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"version": "5.10.258",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.209",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.175",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.142",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.92",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.34",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.0.*",
"status": "unaffected",
"version": "7.0.11",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.1",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbatman-adv: tt: fix negative last_changeset_len\n\nbatadv_piv_tt::last_changeset_len len was declared as s16, but the field is\nnever intended to hold a negative value. When a value greater than 32767 is\nassigned, it wraps to a negative signed integer.\n\nIn batadv_send_my_tt_response(), last_changeset_len is temporarily widened\nto s32. The incorrectly negative s16 value propagates into the s32, causing\nbatadv_tt_prepare_tvlv_local_data() to allocate a full sized buffer but\npopulates only a small portion of it with the collected changeset. All\nremaining bits are kept uninitialized.\n\nUsing an u16 avoids this type confusion and ensures that no (negative) sign\nextension is performed in batadv_send_my_tt_response()."
}
],
"id": "CVE-2026-64089",
"lastModified": "2026-07-20T15:17:08.147",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 9.8,
"baseSeverity": "CRITICAL",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"exploitabilityScore": 3.9,
"impactScore": 5.9,
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary"
}
]
},
"published": "2026-07-19T16:17:49.697",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/179eb62506a02d00370bd6478898cb632e10986c"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/22d59c72f4a47ffec121d0610f70d0d70c3c11c8"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/55dc41fe8821e9a849e147255ad572bc933a9d15"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/6314089acf0ddf64376fdc0b1420695504c73f52"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/c424e8519ac78eac5d9f4eecf06208a0d619ec14"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/d29abf70c665730e249d2ec8e1402095ae26bcee"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/eb235472b52ef36981c5aad330485eaf2382c53b"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/fc92cdfcb295cefa4344d71a527d61b638b7bfc4"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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