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CVE-2022-49520— arm64: compat: Do not treat syscall number as ESR_ELx for a bad syscall

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于将未知系统调用号作为ESR_ELx值处理，可能导致打印错误的异常消息。

AI Predicted 5.5 Difficulty: Easy EPSS 0.30% · P21

Possible ATT&CK Techniques 1 AI

T1499 · Endpoint Denial of Service

Affected Version Matrix 14

VendorProduct Version RangeStatus
Linux Linux 532826f3712b607256eb30f92f23d1c604d3fa34< efd183d988b416fcdf6f7c298a17ced4859ca77d affected
532826f3712b607256eb30f92f23d1c604d3fa34< ad97425d23af3c3b8d4f6a2bb666cb485087c007 affected
532826f3712b607256eb30f92f23d1c604d3fa34< 621916afe8cd4f322eb12759b64a2f938d4e551d affected
532826f3712b607256eb30f92f23d1c604d3fa34< 095e975f8150ccd7f852eb578c1cdbdd2f517c7a affected
532826f3712b607256eb30f92f23d1c604d3fa34< 3910ae71cb963fa2b68e684489d4fc3d105afda0 affected
532826f3712b607256eb30f92f23d1c604d3fa34< 3fed9e551417b84038b15117732ea4505eee386b affected
4.17 affected
< 4.17 unaffected
… +6 more rows
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I. Basic Information for CVE-2022-49520

Vulnerability Information
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Vulnerability Title
arm64: compat: Do not treat syscall number as ESR_ELx for a bad syscall
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: arm64: compat: Do not treat syscall number as ESR_ELx for a bad syscall If a compat process tries to execute an unknown system call above the __ARM_NR_COMPAT_END number, the kernel sends a SIGILL signal to the offending process. Information about the error is printed to dmesg in compat_arm_syscall() -> arm64_notify_die() -> arm64_force_sig_fault() -> arm64_show_signal(). arm64_show_signal() interprets a non-zero value for current->thread.fault_code as an exception syndrome and displays the message associated with the ESR_ELx.EC field (bits 31:26). current->thread.fault_code is set in compat_arm_syscall() -> arm64_notify_die() with the bad syscall number instead of a valid ESR_ELx value. This means that the ESR_ELx.EC field has the value that the user set for the syscall number and the kernel can end up printing bogus exception messages*. For example, for the syscall number 0x68000000, which evaluates to ESR_ELx.EC value of 0x1A (ESR_ELx_EC_FPAC) the kernel prints this error: [ 18.349161] syscall[300]: unhandled exception: ERET/ERETAA/ERETAB, ESR 0x68000000, Oops - bad compat syscall(2) in syscall[10000+50000] [ 18.350639] CPU: 2 PID: 300 Comm: syscall Not tainted 5.18.0-rc1 #79 [ 18.351249] Hardware name: Pine64 RockPro64 v2.0 (DT) [..] which is misleading, as the bad compat syscall has nothing to do with pointer authentication. Stop arm64_show_signal() from printing exception syndrome information by having compat_arm_syscall() set the ESR_ELx value to 0, as it has no meaning for an invalid system call number. The example above now becomes: [ 19.935275] syscall[301]: unhandled exception: Oops - bad compat syscall(2) in syscall[10000+50000] [ 19.936124] CPU: 1 PID: 301 Comm: syscall Not tainted 5.18.0-rc1-00005-g7e08006d4102 #80 [ 19.936894] Hardware name: Pine64 RockPro64 v2.0 (DT) [..] which although shows less information because the syscall number, wrongfully advertised as the ESR value, is missing, it is better than showing plainly wrong information. The syscall number can be easily obtained with strace. *A 32-bit value above or equal to 0x8000_0000 is interpreted as a negative integer in compat_arm_syscal() and the condition scno < __ARM_NR_COMPAT_END evaluates to true; the syscall will exit to userspace in this case with the ENOSYS error code instead of arm64_notify_die() being called.
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于将未知系统调用号作为ESR_ELx值处理，可能导致打印错误的异常消息。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux 532826f3712b607256eb30f92f23d1c604d3fa34 ~ efd183d988b416fcdf6f7c298a17ced4859ca77d -
Linux Linux 4.17 -

II. Public POCs for CVE-2022-49520

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III. Intelligence Information for CVE-2022-49520

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Patches & Fixes for CVE-2022-49520 (6)

Same Patch Batch · Linux · 2025-02-26 · 706 CVEs total

CVE-2022-49561 9.8 CRITICAL netfilter: conntrack: re-fetch conntrack after insertion
CVE-2022-49149 9.8 CRITICAL rxrpc: Fix call timer start racing with call destruction
CVE-2022-49362 9.8 CRITICAL NFSD: Fix potential use-after-free in nfsd_file_put()
CVE-2022-49201 9.8 CRITICAL ibmvnic: fix race between xmit and reset
CVE-2022-49194 9.8 CRITICAL net: bcmgenet: Use stronger register read/writes to assure ordering
CVE-2022-49093 9.8 CRITICAL skbuff: fix coalescing for page_pool fragment recycling
CVE-2022-49260 9.8 CRITICAL crypto: hisilicon/sec - fix the aead software fallback for engine
CVE-2022-49418 9.8 CRITICAL NFSv4: Fix free of uninitialized nfs4_label on referral lookup.
CVE-2022-49094 9.8 CRITICAL net/tls: fix slab-out-of-bounds bug in decrypt_internal
CVE-2022-49407 9.8 CRITICAL dlm: fix plock invalid read
CVE-2022-49280 9.8 CRITICAL NFSD: prevent underflow in nfssvc_decode_writeargs()
CVE-2022-49356 9.8 CRITICAL SUNRPC: Trap RDMA segment overflows
CVE-2022-49058 9.1 CRITICAL cifs: potential buffer overflow in handling symlinks
CVE-2022-49328 8.8 HIGH mt76: fix use-after-free by removing a non-RCU wcid pointer
CVE-2022-49114 8.8 HIGH scsi: libfc: Fix use after free in fc_exch_abts_resp()
CVE-2022-49535 8.8 HIGH scsi: lpfc: Fix null pointer dereference after failing to issue FLOGI and PLOGI
CVE-2022-49470 8.8 HIGH Bluetooth: btmtksdio: fix use-after-free at btmtksdio_recv_event
CVE-2022-49111 8.8 HIGH Bluetooth: Fix use after free in hci_send_acl
CVE-2022-49471 8.8 HIGH rtw89: cfo: check mac_id to avoid out-of-bounds
CVE-2022-49519 8.8 HIGH ath10k: skip ath10k_halt during suspend for driver state RESTARTING

Showing top 20 of 706 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2022-49520

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