Summary
In the Linux kernel, the following vulnerability has been resolved: net: do not sense pfmemalloc...
In the Linux kernel, the following vulnerability has been resolved:
net: do not sense pfmemalloc status in skb_append_pagefrags()
skb_append_pagefrags() is used by af_unix and udp sendpage()
implementation so far.
In commit 326140063946 ("tcp: TX zerocopy should not sense
pfmemalloc status") we explained why we should not sense
pfmemalloc status for pages owned by user space.
We should also use skb_fill_page_desc_noacc()
in skb_append_pagefrags() to avoid following KCSAN report:
BUG: KCSAN: data-race in lru_add_fn / skb_append_pagefrags
write to 0xffffea00058fc1c8 of 8 bytes by task 17319 on cpu 0:
__list_add include/linux/list.h:73 [inline]
list_add include/linux/list.h:88 [inline]
lruvec_add_folio include/linux/mm_inline.h:323 [inline]
lru_add_fn+0x327/0x410 mm/swap.c:228
folio_batch_move_lru+0x1e1/0x2a0 mm/swap.c:246
lru_add_drain_cpu+0x73/0x250 mm/swap.c:669
lru_add_drain+0x21/0x60 mm/swap.c:773
free_pages_and_swap_cache+0x16/0x70 mm/swap_state.c:311
tlb_batch_pages_flush mm/mmu_gather.c:59 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:256 [inline]
tlb_flush_mmu+0x5b2/0x640 mm/mmu_gather.c:263
tlb_finish_mmu+0x86/0x100 mm/mmu_gather.c:363
exit_mmap+0x190/0x4d0 mm/mmap.c:3098
__mmput+0x27/0x1b0 kernel/fork.c:1185
mmput+0x3d/0x50 kernel/fork.c:1207
copy_process+0x19fc/0x2100 kernel/fork.c:2518
kernel_clone+0x166/0x550 kernel/fork.c:2671
__do_sys_clone kernel/fork.c:2812 [inline]
__se_sys_clone kernel/fork.c:2796 [inline]
__x64_sys_clone+0xc3/0xf0 kernel/fork.c:2796
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
read to 0xffffea00058fc1c8 of 8 bytes by task 17325 on cpu 1:
page_is_pfmemalloc include/linux/mm.h:1817 [inline]
__skb_fill_page_desc include/linux/skbuff.h:2432 [inline]
skb_fill_page_desc include/linux/skbuff.h:2453 [inline]
skb_append_pagefrags+0x210/0x600 net/core/skbuff.c:3974
unix_stream_sendpage+0x45e/0x990 net/unix/af_unix.c:2338
kernel_sendpage+0x184/0x300 net/socket.c:3561
sock_sendpage+0x5a/0x70 net/socket.c:1054
pipe_to_sendpage+0x128/0x160 fs/splice.c:361
splice_from_pipe_feed fs/splice.c:415 [inline]
__splice_from_pipe+0x222/0x4d0 fs/splice.c:559
splice_from_pipe fs/splice.c:594 [inline]
generic_splice_sendpage+0x89/0xc0 fs/splice.c:743
do_splice_from fs/splice.c:764 [inline]
direct_splice_actor+0x80/0xa0 fs/splice.c:931
splice_direct_to_actor+0x305/0x620 fs/splice.c:886
do_splice_direct+0xfb/0x180 fs/splice.c:974
do_sendfile+0x3bf/0x910 fs/read_write.c:1255
__do_sys_sendfile64 fs/read_write.c:1323 [inline]
__se_sys_sendfile64 fs/read_write.c:1309 [inline]
__x64_sys_sendfile64+0x10c/0x150 fs/read_write.c:1309
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
value changed: 0x0000000000000000 -> 0xffffea00058fc188
Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 17325 Comm: syz-executor.0 Not tainted 6.1.0-rc1-syzkaller-00158-g440b7895c990-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022
Impact
CVE-2022-50323 has a CVSS score of 5.5 (Medium). The vector is requires local access, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. No fixed version is listed yet, so configuration controls and monitoring matter more in the interim.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2022-50323? CVE-2022-50323 is a medium-severity security vulnerability. No fixed version is listed yet.
- How severe is CVE-2022-50323? CVE-2022-50323 has a CVSS score of 5.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Is there a fix for CVE-2022-50323? No fixed version is listed for CVE-2022-50323 yet. Monitor the advisory for updates and apply mitigations in the interim.
- Is CVE-2022-50323 exploitable, and should I be worried? Whether CVE-2022-50323 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2022-50323 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.