CVE-2026-68386
bpf, sockmap: Reject unhashed UDP sockets on sockmap update
Description
In 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").
INFO
Published Date :
Aug. 10, 2026, 1:20 p.m.
Last Modified :
Aug. 10, 2026, 1:20 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Affected Products
The following products are affected by CVE-2026-68386
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
Solution
- Update the Linux kernel to the latest version.
- Apply relevant patches or security updates.
- Verify socket handling in BPF programs.
- Test for memory leaks after updates.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-68386.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-68386 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-68386
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-68386 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-68386 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Aug. 10, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '0c48eefae712c2fd91480346a07a1a9cd0f9470b', 'lessThan': '7ffe529e7127411806c8692fb1490f552c629dc2', 'versionType': 'git'}, {'status': 'affected', 'version': '0c48eefae712c2fd91480346a07a1a9cd0f9470b', 'lessThan': '17b7ef6b86112a4e61cee1e9009a4b318e3225c5', 'versionType': 'git'}, {'status': 'affected', 'version': '0c48eefae712c2fd91480346a07a1a9cd0f9470b', 'lessThan': '250474c69bc3fc48a5fc21d7c349f279caad947a', 'versionType': 'git'}, {'status': 'affected', 'version': '0c48eefae712c2fd91480346a07a1a9cd0f9470b', 'lessThan': '8692655da369961128658cf8539334b6a960ecb0', 'versionType': 'git'}, {'status': 'affected', 'version': '0c48eefae712c2fd91480346a07a1a9cd0f9470b', 'lessThan': '66efd3368ae10d05e08fbe6425b50fdec7186ac7', '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': '5.15'}, {'status': 'unaffected', 'version': '0', 'lessThan': '5.15', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.6.148', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.101', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.42', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.6', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc4', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/core/sock_map.c'], 'defaultStatus': 'affected'}] Added Description In 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"). Added Reference https://git.kernel.org/stable/c/17b7ef6b86112a4e61cee1e9009a4b318e3225c5 Added Reference https://git.kernel.org/stable/c/250474c69bc3fc48a5fc21d7c349f279caad947a Added Reference https://git.kernel.org/stable/c/66efd3368ae10d05e08fbe6425b50fdec7186ac7 Added Reference https://git.kernel.org/stable/c/7ffe529e7127411806c8692fb1490f552c629dc2 Added Reference https://git.kernel.org/stable/c/8692655da369961128658cf8539334b6a960ecb0