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CVE-2026-53671— PREVAIL: Context-write no-op in do_mem_store allows unsafe eBPF programs to pass verification

Quick assessment

Affected
vbpf prevail
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.

PREVAIL 是一个基于抽象解释层的多项式运行时 eBPF 验证器。在 0.2.4 版本之前，PREVAIL 中的抽象变换器将通过对 T_CTX 类型基址寄存器的写操作视为静默的空操作（no-op）： 中的 函数仅对 T_STACK 的存储进行建模，而检查器中针对 T_CTX 边界的分支从未测试 。攻击者可以构造一个 eBPF 程序，覆盖某个上下文字段（例如 ），将该字段以 类型重新加载，并解引用一个由攻击者控制的地址——而 PREVAIL 仍会错误地报告该程序是安全的。该问题已在 0.2.4 版本中修复。

CVSS 9.3 · Critical

Possible ATT&CK Techniques 1 AI

T1562

Affected Version Matrix 1

VendorProduct Version RangeStatus
vbpf prevail < 0.2.4 affected
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I. Basic Information for CVE-2026-53671

Vulnerability Information
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Vulnerability Title
PREVAIL: Context-write no-op in do_mem_store allows unsafe eBPF programs to pass verification
Source: CVE Program / CVE List V5
Vulnerability Description
PREVAIL is a Polynomial-Runtime EBPF Verifier using an Abstract Interpretation Layer. Prior to version 0.2.4, the abstract transformer in prevail treats writes through a T_CTX-typed base register as a silent no-op: do_mem_store in src/crab/ebpf_transformer.cpp only models T_STACK stores, and the checker's T_CTX bounds arm never tests AccessType::write. An attacker can craft an eBPF program that overwrites a context field (e.g., ctx->data), reload that field typed as T_PACKET, and dereference an attacker-controlled address — and prevail will report the program as safe. This issue has been patched in version 0.2.4.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
Source: CVE Program / CVE List V5
Vulnerability Type
数值计算不正确
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
vbpf prevail < 0.2.4 -

II. Public POCs for CVE-2026-53671

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III. Intelligence Information for CVE-2026-53671

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Patches & Fixes for CVE-2026-53671 (1)

Vendor Advisories for CVE-2026-53671 (1)

Vendor Pages for CVE-2026-53671 (1)

Same Patch Batch · vbpf · 2026-09-02 · 3 CVEs total

CVE-2026-53670 9.3 CRITICAL PREVAIL: Non-singleton typeset in add() skips offset update, allowing OOB access to pass e
CVE-2026-53706 8.8 HIGH PREVAIL: ALU32 pointer arithmetic accepted without is64 gate — verifier emits false PASS f

IV. Related Vulnerabilities

Same product: prevail
Same vendor: vbpf
Same weakness: CWE-682

V. Comments for CVE-2026-53671

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