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CVE-2026-90648: wabt

Severity

7.1 (HIGH)

Vendor

WEBASSEMBLY

Affected versions

0 through 1.0.41

Patch status

Unknown

Published

2026-09-13T00:17:07.023

Modified

2026-09-13T00:17:07.023

Why it matters

This matters because the affected product may allow code execution. Prioritize systems that are internet-facing or have privileged access to other infrastructure.

Recommended admin actions

• Review and patch based on exposure, asset criticality, and business impact.
• Compare installed versions against the affected version range in the advisory.

Technical summary

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).

View the official NVD record for CVE-2026-90648

CVE data is sourced from NVD/CNA records and optional enrichment. Validate against the vendor advisory before taking production action.