CVE-2026-74689

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> net/atm: fix slab-out-of-bounds read in vcc_setsockopt()<br /> <br /> vcc_setsockopt() contained an ineffective optlen check:<br /> if (__SO_LEVEL_MATCH(optname, level) &amp;&amp; optlen != __SO_SIZE(optname))<br /> return -EINVAL;<br /> <br /> If __SO_LEVEL_MATCH(optname, level) evaluated to false (e.g. if the caller<br /> passed a mismatched level), the length check optlen != __SO_SIZE(optname)<br /> was short-circuited and bypassed. Execution then fell through to switch(optname),<br /> calling copy_from_sockptr() assuming optval contained sufficient space.<br /> <br /> Furthermore, even if level matched, a cgroup BPF setsockopt filter could shrink<br /> optlen after entry. Because copy_from_sockptr() on kernel pointers uses memcpy(),<br /> this leads to a KASAN slab-out-of-bounds read when optlen is smaller than the<br /> expected structure size.<br /> <br /> Fix this by using copy_safe_from_sockptr(), which unconditionally validates<br /> that optlen is at least the expected size before copying. Also change the local<br /> &amp;#39;value&amp;#39; variable type from &amp;#39;unsigned long&amp;#39; to &amp;#39;int&amp;#39; so that SO_SETCLP matches<br /> its sizeof(int) ABI encoding on 64-bit systems.