CVE-2026-98629
Status: ReceivedUnscored—
Severity—Unscored
Exploitation probability0.21 %higher than 10% of CVEs
Active exploitationNonot in the CISA catalog
Public exploitNot knownno public code found
In the Linux kernel, the following vulnerability has been resolved:
net/sched: cls_u32: fix manual hash table handle IDR aliasing
A u32 hash table created with an explicit handle ('tc filter add ... handle 801: u32 divisor N') keys its IDR entry on the raw handle, while the destroy paths free it under handle2id(handle). The two key domains disagree for handles in the 0x800..0xFFF htid range: handle2id() folds them back into the auto-allocated id space (1..0x7FF).
A manual table therefore leaves its raw-keyed IDR entry unreachable on delete (a permanent leak), and its delete can drop the idr entry of an unrelated live auto table.
Read full descriptionShow less
A later auto allocation can then hand out a handle that aliases the live manual table; u32_lookup_ht() first-match routes lookups and TCA_U32_LINK for that htid to the wrong table.
Key the divisor-path alloc on handle2id(handle) so allocation and removal share one key domain. A manual handle that maps onto an id already in use is rejected with -ENOSPC, and auto allocation skips ids held by live manual tables.
Also tested with a poc with a live u32 table on the block, add/delete a manual table 'handle 901: u32 divisor 1' twice; unpatched, the re-add fails with -ENOSPC because the raw key leaked on the first delete.
Technical details traces, logs and code from the original report
Conditions to recreate:
ip link add test0 type dummy
tc qdisc add dev test0 clsact
tc filter add dev test0 ingress protocol ip pref 1 \
handle 801: u32 divisor 16
tc filter add dev test0 ingress protocol ip pref 2 u32 divisor 16
tc -d filter show dev test0 ingress | grep 'fh 801:'
# unpatched: two live tables with handle 0x80100000 (the pref 2 root
# hnode is auto-allocated id 1); patched: the auto hnode takes id 2.CVSS
NVD hasn't assigned a CVSS score to this CVE (common since the April 2026 policy change).
Exploitation probability (EPSS)
- Probability of exploitation in the next 30 days
- 0.21 %
- Percentile among all scored CVEs
- 10
- Score date
- 10/20/2026
EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).
Affected technologies (1)
⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.
References
Show 6 references
- https://git.kernel.org/stable/c/0a5f5d9e94dead312d32c366b917c64e552b72f7
- https://git.kernel.org/stable/c/0fac292d93fdb313099e98cce928b3a524c92c94
- https://git.kernel.org/stable/c/21fc07924e996e1e661268ca269c86b8d59d25b3
- https://git.kernel.org/stable/c/2f898f9ec7c73c5697ee462681e7ea6984ee1f3d
- https://git.kernel.org/stable/c/54a454c5e41f5e2cb70c8163140ce095c5d5eefd
- https://git.kernel.org/stable/c/f6696481eedfd5752b4b56eed715d0b0fe48b9c5
Raw JSON (NVD)
Show
{
"id": "CVE-2026-98629",
"cveTags": [],
"metrics": {},
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "9b2c3184e126b941dfa716b8128ed6db92a64e2f",
"lessThan": "21fc07924e996e1e661268ca269c86b8d59d25b3",
"versionType": "git"
},
{
"status": "affected",
"version": "789f9963bd031c3a185605665b744912df8e7eda",
"lessThan": "0fac292d93fdb313099e98cce928b3a524c92c94",
"versionType": "git"
},
{
"status": "affected",
"version": "73af53d82076bbe184d9ece9e14b0dc8599e6055",
"lessThan": "54a454c5e41f5e2cb70c8163140ce095c5d5eefd",
"versionType": "git"
},
{
"status": "affected",
"version": "73af53d82076bbe184d9ece9e14b0dc8599e6055",
"lessThan": "f6696481eedfd5752b4b56eed715d0b0fe48b9c5",
"versionType": "git"
},
{
"status": "affected",
"version": "73af53d82076bbe184d9ece9e14b0dc8599e6055",
"lessThan": "2f898f9ec7c73c5697ee462681e7ea6984ee1f3d",
"versionType": "git"
},
{
"status": "affected",
"version": "73af53d82076bbe184d9ece9e14b0dc8599e6055",
"lessThan": "0a5f5d9e94dead312d32c366b917c64e552b72f7",
"versionType": "git"
},
{
"status": "affected",
"version": "4403f9293ce9ecc2a55c688d84ee37e3ba0fc1a8",
"versionType": "git"
},
{
"status": "affected",
"version": "6.1.119",
"lessThan": "6.1.189",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.6.63",
"lessThan": "6.6.158",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.11.10",
"lessThan": "6.12",
"versionType": "semver"
}
],
"programFiles": [
"net/sched/cls_u32.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.12"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.12",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.1.189",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.158",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.112",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.55",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.9",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/sched/cls_u32.c"
],
"defaultStatus": "affected"
}
]
}
],
"published": "2026-10-18T16:17:15.960",
"references": [
{
"url": "https://git.kernel.org/stable/c/0a5f5d9e94dead312d32c366b917c64e552b72f7",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/0fac292d93fdb313099e98cce928b3a524c92c94",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/21fc07924e996e1e661268ca269c86b8d59d25b3",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/2f898f9ec7c73c5697ee462681e7ea6984ee1f3d",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/54a454c5e41f5e2cb70c8163140ce095c5d5eefd",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/f6696481eedfd5752b4b56eed715d0b0fe48b9c5",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Received",
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: cls_u32: fix manual hash table handle IDR aliasing\n\nA u32 hash table created with an explicit handle ('tc filter add ...\nhandle 801: u32 divisor N') keys its IDR entry on the raw handle, while\nthe destroy paths free it under handle2id(handle). The two key domains\ndisagree for handles in the 0x800..0xFFF htid range:\nhandle2id() folds them back into the auto-allocated id space (1..0x7FF).\n\nA manual table therefore leaves its raw-keyed IDR entry unreachable on\ndelete (a permanent leak), and its delete can drop the idr entry of an\nunrelated live auto table. A later auto allocation can then hand out a\nhandle that aliases the live manual table; u32_lookup_ht() first-match\nroutes lookups and TCA_U32_LINK for that htid to the wrong table.\n\nKey the divisor-path alloc on handle2id(handle) so allocation and\nremoval share one key domain. A manual handle that maps onto an id\nalready in use is rejected with -ENOSPC, and auto allocation skips ids\nheld by live manual tables.\n\nConditions to recreate:\n ip link add test0 type dummy\n tc qdisc add dev test0 clsact\n tc filter add dev test0 ingress protocol ip pref 1 \\\n handle 801: u32 divisor 16\n tc filter add dev test0 ingress protocol ip pref 2 u32 divisor 16\n tc -d filter show dev test0 ingress | grep 'fh 801:'\n # unpatched: two live tables with handle 0x80100000 (the pref 2 root\n # hnode is auto-allocated id 1); patched: the auto hnode takes id 2.\n\nAlso tested with a poc with a live u32 table on the block, add/delete a manual\ntable 'handle 901: u32 divisor 1' twice; unpatched, the re-add fails with\n-ENOSPC because the raw key leaked on the first delete."
}
],
"lastModified": "2026-10-19T10:19:27.130",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}