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CVE-2026-89603— entry: Fix seccomp bypass after ptrace with TSYNC

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基金会开源的一个操作系统内核。 Linux kernel存在安全漏洞，该漏洞源于ptrace与TSYNC操作引发竞争条件，导致seccomp过滤器被绕过，可能允许非特权进程执行本应被禁止的系统调用。

CVSS 8.4 · High EPSS 0.14% · P3

Possible ATT&CK Techniques 1 AI

T1059.001 · PowerShell

Affected Version Matrix 18

VendorProduct Version RangeStatus
Linux Linux 142781e108b13b2b0e8f035cfb5bfbbc8f14d887< eca5ed4200f0be3e91f8a237b1f37582030a93a8 affected
142781e108b13b2b0e8f035cfb5bfbbc8f14d887< 8709e7e1dd7d7de0651e61700edf24f5784f9243 affected
142781e108b13b2b0e8f035cfb5bfbbc8f14d887< 22bb836fc133331982c264227a899d4b26a09706 affected
142781e108b13b2b0e8f035cfb5bfbbc8f14d887< 23001ee5d8631e30192cde6f6d3ccb6805570499 affected
142781e108b13b2b0e8f035cfb5bfbbc8f14d887< 09e8880ce5409bdb84da991b053d7087502c181e affected
142781e108b13b2b0e8f035cfb5bfbbc8f14d887< 459f33f82864723a7fa366cf1091d9c6c893b6b2 affected
142781e108b13b2b0e8f035cfb5bfbbc8f14d887< ab4647459098a43e9d6fdb860836f08c962f3774 affected
142781e108b13b2b0e8f035cfb5bfbbc8f14d887< 4a3591287fb7f808e209b4974ed337f609a2006b affected
… +10 more rows
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I. Basic Information for CVE-2026-89603

Vulnerability Information
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Vulnerability Title
entry: Fix seccomp bypass after ptrace with TSYNC
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: entry: Fix seccomp bypass after ptrace with TSYNC Sashiko review pointed out the following issue. If a thread is stopped in syscall_trace_enter() for ptrace, another thread can install a seccomp filter with SECCOMP_FILTER_FLAG_TSYNC (e.g., via seccomp_attach_filter()). This will successfully set SYSCALL_WORK_SECCOMP on the stopped thread, but syscall_trace_enter() evaluates a cached 'work' variable sampled on entry. Consequently, the subsequent check for SYSCALL_WORK_SECCOMP misses the newly assigned flag, and the filter is silently bypassed. This race condition could allow an unprivileged process to execute a prohibited system call (e.g., execve) that the newly installed filter was intended to block, especially since the tracer might have modified the system call number during the ptrace stop. Fix this by re-reading the syscall_work flags after ptrace handling, so that any new SYSCALL_WORK_SECCOMP flag set by another thread via TSYNC during the ptrace stop is observed before the subsequent seccomp check.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N
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基金会开源的一个操作系统内核。 Linux kernel存在安全漏洞，该漏洞源于ptrace与TSYNC操作引发竞争条件，导致seccomp过滤器被绕过，可能允许非特权进程执行本应被禁止的系统调用。
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 142781e108b13b2b0e8f035cfb5bfbbc8f14d887 ~ eca5ed4200f0be3e91f8a237b1f37582030a93a8 -
Linux Linux 5.9 -

II. Public POCs for CVE-2026-89603

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III. Intelligence Information for CVE-2026-89603

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Patches & Fixes for CVE-2026-89603 (7)

Other References for CVE-2026-89603 (1)

Same Patch Batch · Linux · 2026-09-11 · 431 CVEs total

CVE-2026-89688 9.8 CRITICAL nfsd: drop the stateid, not the stateowner, on seqid_op replay retry
CVE-2026-89656 9.8 CRITICAL libceph: reject buckets with mismatched CRUSH ids
CVE-2026-89655 9.8 CRITICAL ceph: fix UAF in __kick_flushing_caps() on cf entry freed during unlock
CVE-2026-89658 9.8 CRITICAL NFSD: Prevent client use-after-free during NFSv4.0 revoked-state cleanup
CVE-2026-89660 9.8 CRITICAL NFSD: Prevent client use-after-free during admin state revocation
CVE-2026-89659 9.8 CRITICAL NFSD: Prevent client use-after-free during delegation revoke
CVE-2026-89662 9.8 CRITICAL NFSD: Prevent lock owner use-after-free during client teardown
CVE-2026-89669 9.8 CRITICAL nfsd: initialize copy-notify stateid before publishing it
CVE-2026-89674 9.8 CRITICAL nfsd: fix XDR length calculation in nfsd4_ff_encode_layoutget
CVE-2026-89675 9.8 CRITICAL nfsd: fix UAF in async copy cancel and shutdown
CVE-2026-89676 9.8 CRITICAL nfsd: fix stale s2s_cp_stateids IDR entry for async COPY
CVE-2026-89677 9.8 CRITICAL nfsd: fix possible fh_compose of wrong dentry in nfsd4_create_file()
CVE-2026-89681 9.8 CRITICAL nfsd: fix layout fence worker double-reference race
CVE-2026-89686 9.8 CRITICAL nfsd: fix BUG_ON in nfsd4_alloc_layout_stateid on racing delegation revoke
CVE-2026-89703 9.8 CRITICAL nfsd: set SC_STATUS_FREED in nfsd4_drop_revoked_stid for delegations
CVE-2026-89479 9.8 CRITICAL sctp: stop processing a packet once its association is deleted
CVE-2026-89478 9.8 CRITICAL sctp: drop a chunk if its transport was removed
CVE-2026-89702 9.8 CRITICAL nfsd: size fh_verify server sockaddr slot by xpt_locallen
CVE-2026-89482 9.8 CRITICAL nvme-tcp: do not accept C2HData based on blk_rq_payload_bytes() alone
CVE-2026-89708 9.8 CRITICAL nfsd: RCU-protect cl_cb_session to fix use-after-free on session teardown

Showing top 20 of 431 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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