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High

Race condition in Linux kernel espintcp_close()

IdentifiersCVE-2026-23239CWE-362· Concurrent Execution using Shared…

CVE-2026-23239 is a Linux kernel race condition in the espintcp component, specifically in espintcp_close(). After espintcp_close() calls cancel_work_sync(&ctx->work), the espintcp_tx_work() worker can still be scheduled from other execution paths, including the Delayed ACK handler and ksoftirqd. This creates a window where queued work executes after teardown has progressed, causing espintcp_tx_work() to dereference a freed espintcp context (ctx) or socket structure (sk). The upstream fix replaces cancel_work_sync() with disable_work_sync() to prevent the work item from being rescheduled during close, eliminating the use-after-free condition caused by the race.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation can lead to a use-after-free in kernel context when espintcp_tx_work() accesses freed espintcp ctx or sk objects. The resulting impact can include kernel memory corruption, denial of service through kernel crash or panic, and potentially privilege escalation or other compromise of confidentiality, integrity, and availability depending on exploitability in the affected environment.

Mitigation

If you can’t patch tonight, do this now.

If immediate patching is not possible, reduce exposure by limiting use of the affected espintcp functionality and minimizing access for unprivileged local users who could reach the vulnerable kernel paths. Because this is a kernel race condition in asynchronous work handling, there is no complete mitigation short of deploying a fixed kernel. Standard hardening measures such as restricting local access and reducing attack surface may lower risk but do not remove the vulnerability.

Remediation

Patch, then assume compromise.

Apply a Linux kernel update that includes the upstream espintcp fix replacing cancel_work_sync() with disable_work_sync() in espintcp_close(). Reported fixed package versions in SUSE advisories include, depending on product line, kernel-default >= 5.14.21-150400.24.219.1, >= 5.14.21-150500.55.166.1, >= 6.4.0-46.1, >= 6.4.0-150600.23.112.1, >= 6.4.0-150700.53.55.1, and >= 6.12.0-160000.28.1; openSUSE Tumbleweed lists fixed kernel packages at 6.19.8-1.1. Reboot after installing the updated kernel.
PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType
LinuxLinux Kerneloperating_system

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ACTIVITY FEED

Recent activity

8 sources tracked across advisories and community write-ups. News coverage will land here when it surfaces.

No news coverage yet. Advisories and community discussion only.

What this page doesn’t show

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Exposure mapping

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Threat actor evidence

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Associated malware

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Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity

Community discussion across Reddit, Mastodon, and other social sources.