GHSA-cq66-2f6w-rhg5

Опубликовано: 25 сент. 2026

Источник: github

Github: Не прошло ревью

Описание

In the Linux kernel, the following vulnerability has been resolved:

af_unix: Update last skb marker in manage_oob().

Fahad Alharbi reported that blocking recv(MSG_PEEK) could hog CPU due to OOB skb.

In the following cases, manage_oob() skips OOB skb(s) and returns NULL for the last recv(MSG_PEEK):

socketpair(AF_UNIX, SOCK_STREAM, 0, sk);

skb -> OOB skb -> NULL send(sk[0], "ab", 2, MSG_OOB); recv(sk[1], buf, 0, MSG_PEEK);
skb -> consumed OOB skb -> NULL send(sk[0], "ab", 2, MSG_OOB); recv(sk[1], buf, 1, MSG_OOB); recv(sk[1], buf, 0, MSG_PEEK);
consumed OOB skb -> OOB skb -> NULL send(sk[0], "a", 1, MSG_OOB); recv(sk[1], buf, 0, MSG_OOB); send(sk[0], "b", 1, MSG_OOB); recv(sk[1], buf, 1, MSG_PEEK);

Then, @copied is 0 in unix_stream_read_generic() (zero-length buffer, or non-OOB skb is not yet consumed), and unix_stream_data_wait() is called.

However, it returns immediately because @last is not updated in unix_strea...

In the Linux kernel, the following vulnerability has been resolved:

af_unix: Update last skb marker in manage_oob().

Fahad Alharbi reported that blocking recv(MSG_PEEK) could hog CPU due to OOB skb.

In the following cases, manage_oob() skips OOB skb(s) and returns NULL for the last recv(MSG_PEEK):

socketpair(AF_UNIX, SOCK_STREAM, 0, sk);

skb -> OOB skb -> NULL send(sk[0], "ab", 2, MSG_OOB); recv(sk[1], buf, 0, MSG_PEEK);
skb -> consumed OOB skb -> NULL send(sk[0], "ab", 2, MSG_OOB); recv(sk[1], buf, 1, MSG_OOB); recv(sk[1], buf, 0, MSG_PEEK);
consumed OOB skb -> OOB skb -> NULL send(sk[0], "a", 1, MSG_OOB); recv(sk[1], buf, 0, MSG_OOB); send(sk[0], "b", 1, MSG_OOB); recv(sk[1], buf, 1, MSG_PEEK);

Then, @copied is 0 in unix_stream_read_generic() (zero-length buffer, or non-OOB skb is not yet consumed), and unix_stream_data_wait() is called.

However, it returns immediately because @last is not updated in unix_stream_read_generic(), and the thread busy-waits for a new skb.

Let's update @last in manage_oob().

For MSG_PEEK, @last is updated with the skipped OOB, and for the non-peek case, @last matches the returned value (when !copied) because OOB is unlinked.

Note that manage_oob() is inlined and no stack canary is added.

Ссылки

EPSS

Процентиль: 6%

0.00168

Низкий

CVE ID

CVE-2026-97985

Связанные уязвимости

CVE-2026-97985

ubuntu

18 дней назад

In the Linux kernel, the following vulnerability has been resolved: af_unix: Update last skb marker in manage_oob(). Fahad Alharbi reported that blocking recv(MSG_PEEK) could hog CPU due to OOB skb. In the following cases, manage_oob() skips OOB skb(s) and returns NULL for the last recv(MSG_PEEK): socketpair(AF_UNIX, SOCK_STREAM, 0, sk); 1) skb -> OOB skb -> NULL send(sk[0], "ab", 2, MSG_OOB); recv(sk[1], buf, 0, MSG_PEEK); 2) skb -> consumed OOB skb -> NULL send(sk[0], "ab", 2, MSG_OOB); recv(sk[1], buf, 1, MSG_OOB); recv(sk[1], buf, 0, MSG_PEEK); 3) consumed OOB skb -> OOB skb -> NULL send(sk[0], "a", 1, MSG_OOB); recv(sk[1], buf, 0, MSG_OOB); send(sk[0], "b", 1, MSG_OOB); recv(sk[1], buf, 1, MSG_PEEK); Then, @copied is 0 in unix_stream_read_generic() (zero-length buffer, or non-OOB skb is not yet consumed), and unix_stream_data_wait() is called. However, it returns immediately because @last is not updated in unix_stream_read_generic(), and the thread busy-waits for a new skb. Let...