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CVE-2026-90648

Quick assessment

Affected
WebAssembly wabt
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.

wabt 中的 wasm2c（版本 1.0.41 及之前）在某些情况下允许沙箱逃逸，主要发生在 32 位平台上，也被称为“table flip”攻击。 在 中的 函数里，代码没有检查 的返回值。当函数引用（funcref）表分配失败时， 被置为 ，但 仍保持为客户端声明的元素数量；因此边界检查仍然通过，而表元素访问会解析为绝对内存地址（即 ）。这使得攻击者能够随意读写宿主进程的内存，并通过 、 和 实现任意代码执行，从而破坏了 wasm2c 所提供隔离机制，导致完整的沙箱逃逸。 wasm2c 被 RLBox 和 W

CVSS 7.1 · High
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I. Basic Information for CVE-2026-90648

Vulnerability Information
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Vulnerability Title
N/A
Source: CVE Program / CVE List V5
Vulnerability Description
wasm2c in WebAssembly wabt through 1.0.41 allows sandbox escape in some situations that primarily involve 32-bit platforms, aka a "table flip" attack. It does not check the return value of calloc() in wasm_rt_allocate_funcref_table() (wasm2c/wasm-rt-impl-tableops.inc). When the funcref table allocation fails, table->data is left NULL while table->size keeps the guest-declared element count; thus, bounds checks still pass and table element accesses resolve to absolute memory addresses (i * sizeof(wasm_rt_funcref_t)). This gives arbitrary read and write of host process memory and - via table.get, table.set, and call_indirect - arbitrary code execution, defeating the isolation that wasm2c exists to provide (a full sandbox escape). wasm2c is used as an in-process sandboxing boundary by RLBox and WasmBoxC, including in Firefox, which compiles the Graphite, Hunspell, Ogg, Expat, and Woff2 libraries via wasm2c to contain untrusted font, media, and XML input. Therefore, sandboxing in these applications is potentially affected. Exploitation requires the funcref table allocation to fail, for example under an address-space limit (RLIMIT_AS), on 32-bit hosts, with vm.overcommit_memory=2, or under memory pressure. On 64-bit Linux with default overcommit the allocation succeeds and the defect is not triggered. The wasm2c memory allocator aborts on calloc failure in the same runtime; the table allocator lacks this abort behavior. This was introduced in commit ab9e0b55 (PR #813).
Source: CVE Program / CVE List V5
CVSS Information
CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:H/SA:H
Source: CVE Program / CVE List V5
Vulnerability Type
未加检查的返回值
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
WebAssembly wabt 0 ~ 1.0.41 -

II. Public POCs for CVE-2026-90648

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III. Intelligence Information for CVE-2026-90648

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Proof of Concept for CVE-2026-90648 (1)

Vendor Pages for CVE-2026-90648 (1)

Other References for CVE-2026-90648 (1)

IV. Related Vulnerabilities

Same product: wabt
Same vendor: WebAssembly
Same weakness: CWE-252

V. Comments for CVE-2026-90648

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