CVE-2026-98588
In the Linux kernel, the following vulnerability has been resolved:
bpf, sockmap: Reject max_entries > INT_MAX in sock_map_alloc
sock_map_alloc() only rejects max_entries == 0 and otherwise allows any u32 value. sock_map_free() then walks the sks[] array with a signed int iterator:
When a SOCKMAP is created with max_entries = 0xffffffff (UINT_MAX), the allocation of 32 GiB can succeed on large-memory hosts. During free the counter reaches 0x80000000, wraps to INT_MIN, is sign-extended by movslq and turned into a ~16 GiB negative offset from stab->sks, pointing far below the allocation.
The faulting access is an xchg() write in sock_map_free(). Without KASAN, the same out-of-bounds write can fault on an unmapped vmalloc page or corrupt an unrelated allocation if that vmalloc address is populated. On a KASAN kernel with CONFIG_KASAN_VMALLOC=y, the shadow check for that address hits an unmapped shadow page and oopses first:
Read full descriptionShow less
Vmcore confirmed stab->map.max_entries == 0xffffffff, stab->sks == 0xffffc911ace2d000, and the faulting address sks + (s64)INT_MIN * 8 exactly at 0xffffc90dace2d000. The same buggy path is reached on the normal close()/bpf_map_free_deferred() path whenever such a map is destroyed.
sock_map_alloc() used to bound its allocation size through bpf_map_charge_init(), but the bound was dropped when rlimit-based memory accounting was removed. Reject max_entries > INT_MAX at creation time so the signed iterator in sock_map_free() never sees a value that would overflow.
Triggered by syzkaller and reproduced on both a 6.6-based KASAN kernel and the upstream v7.3-rc2 kernel.
Technical details traces, logs and code from the original report
int i; for (i = 0; i < stab->map.max_entries; i++) struct sock **psk = &stab->sks[i]; BUG: unable to handle page fault for address: fffff521b59c5a00 RIP: 0010:kasan_check_range+0x107/0x190 Call Trace: sock_map_free+0x93/0x190 map_create+0x68d/0xb30 __sys_bpf+0x21e/0x2e70
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 7 references
- https://git.kernel.org/stable/c/814a81c842bd88f6bd8a4ce550d560df071a5d03
- https://git.kernel.org/stable/c/909f761868fda329dc69130ef9eb5b5795bcdf00
- https://git.kernel.org/stable/c/ba7d627dbc67d62df2fa66d7b41e743c3ace0ec8
- https://git.kernel.org/stable/c/c56191af3a578b9cc265fa3bd5fc0752c59c1781
- https://git.kernel.org/stable/c/cc70972ddbf0e3398f2f32624d31db78594d50d8
- https://git.kernel.org/stable/c/cea597519b9ca6d691c98d92460ead8ece2a07af
- https://git.kernel.org/stable/c/f4a73f49e256bd835368504462be3b57b03febff
Raw JSON (NVD)
Show
{
"id": "CVE-2026-98588",
"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": "0d2c4f9640501ff57ba0be1f5644a02c29a02fa1",
"lessThan": "f4a73f49e256bd835368504462be3b57b03febff",
"versionType": "git"
},
{
"status": "affected",
"version": "0d2c4f9640501ff57ba0be1f5644a02c29a02fa1",
"lessThan": "c56191af3a578b9cc265fa3bd5fc0752c59c1781",
"versionType": "git"
},
{
"status": "affected",
"version": "0d2c4f9640501ff57ba0be1f5644a02c29a02fa1",
"lessThan": "909f761868fda329dc69130ef9eb5b5795bcdf00",
"versionType": "git"
},
{
"status": "affected",
"version": "0d2c4f9640501ff57ba0be1f5644a02c29a02fa1",
"lessThan": "cc70972ddbf0e3398f2f32624d31db78594d50d8",
"versionType": "git"
},
{
"status": "affected",
"version": "0d2c4f9640501ff57ba0be1f5644a02c29a02fa1",
"lessThan": "cea597519b9ca6d691c98d92460ead8ece2a07af",
"versionType": "git"
},
{
"status": "affected",
"version": "0d2c4f9640501ff57ba0be1f5644a02c29a02fa1",
"lessThan": "ba7d627dbc67d62df2fa66d7b41e743c3ace0ec8",
"versionType": "git"
},
{
"status": "affected",
"version": "0d2c4f9640501ff57ba0be1f5644a02c29a02fa1",
"lessThan": "814a81c842bd88f6bd8a4ce550d560df071a5d03",
"versionType": "git"
}
],
"programFiles": [
"net/core/sock_map.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "5.11"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "5.11",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.15.222",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"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/core/sock_map.c"
],
"defaultStatus": "affected"
}
]
}
],
"published": "2026-10-18T16:17:11.393",
"references": [
{
"url": "https://git.kernel.org/stable/c/814a81c842bd88f6bd8a4ce550d560df071a5d03",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/909f761868fda329dc69130ef9eb5b5795bcdf00",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/ba7d627dbc67d62df2fa66d7b41e743c3ace0ec8",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/c56191af3a578b9cc265fa3bd5fc0752c59c1781",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/cc70972ddbf0e3398f2f32624d31db78594d50d8",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/cea597519b9ca6d691c98d92460ead8ece2a07af",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/f4a73f49e256bd835368504462be3b57b03febff",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Received",
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf, sockmap: Reject max_entries > INT_MAX in sock_map_alloc\n\nsock_map_alloc() only rejects max_entries == 0 and otherwise allows any\nu32 value. sock_map_free() then walks the sks[] array with a signed int\niterator:\n\n\tint i;\n\tfor (i = 0; i < stab->map.max_entries; i++)\n\t\tstruct sock **psk = &stab->sks[i];\n\nWhen a SOCKMAP is created with max_entries = 0xffffffff (UINT_MAX), the\nallocation of 32 GiB can succeed on large-memory hosts. During free the\ncounter reaches 0x80000000, wraps to INT_MIN, is sign-extended by movslq\nand turned into a ~16 GiB negative offset from stab->sks, pointing far\nbelow the allocation.\n\nThe faulting access is an xchg() write in sock_map_free(). Without\nKASAN, the same out-of-bounds write can fault on an unmapped vmalloc page\nor corrupt an unrelated allocation if that vmalloc address is populated.\nOn a KASAN kernel with CONFIG_KASAN_VMALLOC=y, the shadow check for that\naddress hits an unmapped shadow page and oopses first:\n\n BUG: unable to handle page fault for address: fffff521b59c5a00\n RIP: 0010:kasan_check_range+0x107/0x190\n Call Trace:\n sock_map_free+0x93/0x190\n map_create+0x68d/0xb30\n __sys_bpf+0x21e/0x2e70\n\nVmcore confirmed stab->map.max_entries == 0xffffffff, stab->sks ==\n0xffffc911ace2d000, and the faulting address sks + (s64)INT_MIN * 8\nexactly at 0xffffc90dace2d000. The same buggy path is reached on the\nnormal close()/bpf_map_free_deferred() path whenever such a map is\ndestroyed.\n\nsock_map_alloc() used to bound its allocation size through\nbpf_map_charge_init(), but the bound was dropped when rlimit-based memory\naccounting was removed. Reject max_entries > INT_MAX at creation time so\nthe signed iterator in sock_map_free() never sees a value that would\noverflow.\n\nTriggered by syzkaller and reproduced on both a 6.6-based KASAN kernel\nand the upstream v7.3-rc2 kernel."
}
],
"lastModified": "2026-10-19T10:19:19.777",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}