af_unix: Fix UAF read of tail->len in unix_stream_data_wait()
In the Linux kernel, the following vulnerability has been resolved: af_unix: Fix UAF read of tail->len in unix_stream_data_wait() unix_stream_data_wait() does skb_peek_tail(&sk->sk_receive_queue) without holding any lock that prevents SKBs on that queue from being dequeued and freed. This has been the case since commit 79f632c71bea ("unix/stream: fix peeking with an offset larger than data in queue"). The first consequence of this is that the pointer comparison `tail != last` can be false even if `last` semantically refers to an already-freed SKB while `tail` is a new SKB allocated at the same address; which can cause unix_stream_data_wait() to wrongly keep blocking after new data has arrived, but only in a weird scenario where a peeking recv() and a normal recv() on the same socket are racing, which is probably not a real problem. But since commit 2b514574f7e8 ("net: af_unix: implement splice for stream af_unix sockets"), `tail` is actually dereferenced, which can cause UAF in the following race scenario (where test_setup() runs single-threaded, and afterwards, test_thread1() and test_thread2() run concurrently in two threads: ``` static int socks[2]; void test_setup(void) { socketpair(AF_UNIX, SOCK_STREAM, 0, socks); send(socks[1], "A", 1, 0); int peekoff = 1; setsockopt(socks[0], SOL_SOCKET, SO_PEEK_OFF, &peekoff, sizeof(peekoff)); } void test_thread1(void) { char dummy; recv(socks[0], &dummy, 1, MSG_PEEK); } void test_thread2(void) { char dummy; recv(socks[0], &dummy, 1,
CVE-2026-64109
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-64109
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "2b514574f7e88c8498027ee366fd6e7aae5aa4b5",
"lessThan": "26342087fac93b3932e6af61dc91ec029cb8a623",
"versionType": "git"
},
{
"status": "affected",
"version": "2b514574f7e88c8498027ee366fd6e7aae5aa4b5",
"lessThan": "38bccb927d83d7d52e5b20015a172a0b6101d11e",
"versionType": "git"
},
{
"status": "affected",
"version": "2b514574f7e88c8498027ee366fd6e7aae5aa4b5",
"lessThan": "acdff9907478e82208475b1151700d0b71dcdc63",
"versionType": "git"
},
{
"status": "affected",
"version": "2b514574f7e88c8498027ee366fd6e7aae5aa4b5",
"lessThan": "5f162f95a95834f06a8ec6140889272ad12e842f",
"versionType": "git"
},
{
"status": "affected",
"version": "2b514574f7e88c8498027ee366fd6e7aae5aa4b5",
"lessThan": "be309f8eae8b474a4a617eaae01324da996fc719",
"versionType": "git"
}
],
"programFiles": [
"net/unix/af_unix.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "4.2"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "4.2",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.6.143",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.92",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.34",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.0.11",
"versionType": "semver",
"lessThanOrEqual": "7.0.*"
},
{
"status": "unaffected",
"version": "7.1",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/unix/af_unix.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-64109
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #40954 · Revision 1
- Added to Heist Feed
- Publisher date