bpf, sockmap: Reject unhashed UDP sockets on sockmap update

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-68386
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-10 13:20:31 UTC
Updated2026-08-19 17:20:47 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: bpf, sockmap: Reject unhashed UDP sockets on sockmap update UDP sockets get SOCK_RCU_FREE set when (auto-)bound. This means sk_is_refcounted(unbound) = true, while sk_is_refcounted(bound) = false. Because sockmap accepts unbound UDP sockets, a BPF program can increment a socket's refcount via lookup. If the socket is subsequently bound, the transition from unbound to bound causes bpf_sk_release() to skip the decrement of the refcount, causing a memory leak. unreferenced object 0xffff88810bc2eb40 (size 1984): comm "test_progs", pid 2451, jiffies 4295320596 hex dump (first 32 bytes): 7f 00 00 01 7f 00 00 01 d2 04 1b b7 04 d2 00 00 ................ 02 00 01 40 00 00 00 00 00 00 00 00 00 00 00 00 ...@............ backtrace (crc bdee079d): kmem_cache_alloc_noprof+0x557/0x660 sk_prot_alloc+0x69/0x240 sk_alloc+0x30/0x460 inet_create+0x2ce/0xf80 __sock_create+0x25b/0x5c0 __sys_socket+0x119/0x1d0 __x64_sys_socket+0x72/0xd0 do_syscall_64+0xa1/0x5f0 entry_SYSCALL_64_after_hwframe+0x76/0x7e Instead of special-casing for refcounted sockets, reject unhashed UDP sockets during sockmap updates, as there is no benefit to supporting those. This effectively reverts the commit under Fixes, with two exceptions: 1. sock_map_sk_state_allowed() maintains a fall-through `return true`. 2. In the spirit of commit b8b8315e39ff ("bpf, sockmap: Remove unhash handler for BPF sockmap usage"), the proto::unhash BPF handler is not reintroduced. Historical note: this issue is related to commit 67312adc96b5 ("bpf: reject unhashed sockets in bpf_sk_assign").

Risk And Classification

EPSS: 0.002000000 probability, percentile 0.101830000 (date 2026-08-19)

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 0c48eefae712c2fd91480346a07a1a9cd0f9470b 2271276ac5279d2d204be7739a1a28d4ef6cf608 git Not specified
CNA Linux Linux affected 0c48eefae712c2fd91480346a07a1a9cd0f9470b 7ffe529e7127411806c8692fb1490f552c629dc2 git Not specified
CNA Linux Linux affected 0c48eefae712c2fd91480346a07a1a9cd0f9470b 17b7ef6b86112a4e61cee1e9009a4b318e3225c5 git Not specified
CNA Linux Linux affected 0c48eefae712c2fd91480346a07a1a9cd0f9470b 250474c69bc3fc48a5fc21d7c349f279caad947a git Not specified
CNA Linux Linux affected 0c48eefae712c2fd91480346a07a1a9cd0f9470b 8692655da369961128658cf8539334b6a960ecb0 git Not specified
CNA Linux Linux affected 0c48eefae712c2fd91480346a07a1a9cd0f9470b 66efd3368ae10d05e08fbe6425b50fdec7186ac7 git Not specified
CNA Linux Linux affected 5.15 Not specified
CNA Linux Linux unaffected 5.15 semver Not specified
CNA Linux Linux unaffected 6.1.183 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.148 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.101 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.42 6.18.* semver Not specified
CNA Linux Linux unaffected 7.1.6 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/17b7ef6b86112a4e61cee1e9009a4b318e3225c5 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/2271276ac5279d2d204be7739a1a28d4ef6cf608 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/66efd3368ae10d05e08fbe6425b50fdec7186ac7 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/8692655da369961128658cf8539334b6a960ecb0 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/7ffe529e7127411806c8692fb1490f552c629dc2 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/250474c69bc3fc48a5fc21d7c349f279caad947a 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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