CVE-2026-98588bpf, sockmap: Reject max_entries > INT_MAX in sock_map_alloc

Description

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: int i; for (i = 0; i < stab->map.max_entries; i++) struct sock **psk = &stab->sks[i]; 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: 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 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.

Timeline

Scores

No CVSS score yet: neither the CNA, CISA nor NVD has scored this CVE. NVD status: Received.

EPSS (exploitation in 30 days)

0.21% · top 89% of all CVEs (15 Nov 2026)

The list uses the assigner's score when there is one, then CISA's, then NVD's: Not scored.

Affected products

• Linux · Linux

  • affected 0d2c4f9640501ff57ba0be1f5644a02c29a02fa1 – < f4a73f49e256bd835368504462be3b57b03febff
  • affected 0d2c4f9640501ff57ba0be1f5644a02c29a02fa1 – < c56191af3a578b9cc265fa3bd5fc0752c59c1781
  • affected 0d2c4f9640501ff57ba0be1f5644a02c29a02fa1 – < 909f761868fda329dc69130ef9eb5b5795bcdf00
  • affected 0d2c4f9640501ff57ba0be1f5644a02c29a02fa1 – < cc70972ddbf0e3398f2f32624d31db78594d50d8
  • affected 0d2c4f9640501ff57ba0be1f5644a02c29a02fa1 – < cea597519b9ca6d691c98d92460ead8ece2a07af
  • affected 0d2c4f9640501ff57ba0be1f5644a02c29a02fa1 – < ba7d627dbc67d62df2fa66d7b41e743c3ace0ec8
  • affected 0d2c4f9640501ff57ba0be1f5644a02c29a02fa1 – < 814a81c842bd88f6bd8a4ce550d560df071a5d03

• Linux · Linux

  • affected 5.11
  • unaffected < 5.11
  • unaffected 5.15.222 – ≤ 5.15.*
  • unaffected 6.1.189 – ≤ 6.1.*
  • unaffected 6.6.158 – ≤ 6.6.*
  • unaffected 6.12.112 – ≤ 6.12.*
  • unaffected 6.18.55 – ≤ 6.18.*
  • unaffected 7.2.9 – ≤ 7.2.*
  • unaffected 7.3 – ≤ *

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• EUVD EUVD-2026-103633 (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

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Record last updated 19 Oct 2026, 09:22 UTC.